Ultraviolet shielding composite fine particles, method for producing the same, and cosmetics

ABSTRACT

The present invention is directed to ultraviolet shielding composite fine particles having transparency in a visible light region include (a) matrix particles comprising an aggregate of primary particles having an average particle diameter of from 0.001 to 0.3 μm, the aggregate being formed while the primary particles retain their shapes; and (b) daughter particles having an average particle diameter of from 0.001 to 0.1 μm, the daughter particles being dispersed in and supported by the matrix particles. In the composite fine particles, the daughter particles have a smaller band gap energy than the particles constituting the matrix particles and are capable of absorbing ultraviolet light, and the resulting ultraviolet shielding composite fine particles have substantially no catalytic activity.

TECHNICAL FIELD

The present invention relates to ultraviolet shielding composite fineparticles having substantially no catalytic activity, having hightransparency in the visible light region, and a high shielding abilityin the ultraviolet light region. It also relates to a method forproducing the composite fine particles, and cosmetics containing suchcomposite fine particles.

BACKGROUND ART

The sunlight reaching the earth includes infrared light, visible light,and ultraviolet light, of which 5 to 6% is ultraviolet light. Theultraviolet light has short wavelengths, which are thus high-energyelectromagnetic waves. Therefore, the ultraviolet light is known todecompose many kinds of materials and to damage living organisms.

Therefore, ultraviolet shielding agents are used for protecting skinfrom inflammation or skin cancer due to exposure of the skin to harmfulultraviolet light. For this purpose, the ultraviolet shielding agentsare added to cosmetics. Also, they are used to prevent pigments fromfading due to decomposition by ultraviolet light. For this purpose, theultraviolet shielding agents are mixed with paints; however, this maycause unnatural skin whitening and a color change of paints. This can beprevented by increasing the transparency of such cosmetics or paints inthe visible light region. Therefore, the ultraviolet light is desirablyblocked while the transparency in the visible light region ismaintained.

The ultraviolet shielding agent comprising organic compounds aseffective ingredients prevents the transmission of the ultraviolet lighton account of the above organic compounds which absorb the ultravioletlight. For example, an ultraviolet absorbent composition comprisingsubstituted N,N'-bis-aromatic formamidines is known (Japanese PatentExamined Publication No. 61-09993). However, the organic ultravioletshielding agents have the problem that although they can absorb theultraviolet light, they are at the same time likely to be decomposed bythe ultraviolet light, with the result of an undesirable lowering of theshielding ability over time. Regarding their application to cosmetics,the kinds and amounts of the ultraviolet shielding agents are restrictedowing to deleterious effects caused on human bodies, and thus it isdifficult to achieve a good shielding performance within a controlledrange.

On the other hand, the ultraviolet shielding agent comprising aninorganic compound contains inorganic fine particles and prevents thetransmission of ultraviolet light by the absorbing ability and thescattering ability of the composition. The inorganic ultravioletshielding agent is superior to the organic ultraviolet shielding agentbecause the composition containing the inorganic ultraviolet shieldingagent is not decomposed by the ultraviolet light with the passage oftime and has little effects on the human body.

However, since the inorganic ultraviolet shielding agents are present inthe form of particles, it is more difficult with inorganic ultravioletshielding agents when compared with organic ultraviolet shielding agentsto block the ultraviolet light while maintaining high transparency inthe visible light region.

In order to possess an effective light shielding ability in theultraviolet light region while maintaining high transparency in thevisible light region (light wavelengths of from 400 to 800 nm), thecomposition has to be microgranulated to give ultrafine particlescapable of being highly dispersed so as to increase the ultravioletscattering ability. However, in the case of using ultrafine particles,dispersion stability problems may arise due to the aggregation of theultrafine particles and the catalytic activities of the ultrafineparticles.

In order to improve dispersibility, the ultrafine particle surfaces maybe coated with other materials For example, skin cosmetics comprising anoily cosmetic base material and a hydrophobic titanium oxide powder areknown (Japanese Patent Examined Publication No. 59-15885). However, asuitable solvent has to be selected depending upon the properties of thematerials coated on the surface. Also, since the particles are stillultrafine, the aggregation of the ultrafine particles can only belowered to a limited extent even if the surface treatment is conducted.In publications other than those mentioned above, there have been knowncosmetics containing a powder obtainable by coating titanium oxide witha particular amount of mixed hydrates comprising silicate hydrates andaluminum hydrates, titanium oxide being nearly spherical or irregularlyshaped and having an average particle diameter of from 30 to 70 nm,wherein the surface of the hydrate-coated titanium oxide is optionallyfurther coated with a silicone oil (Japanese Patent Laid-Open No.2-247109). However, since in this publication the above powder isobtained by drying and pulverization of the product obtained aftercoating with the mixed hydrates comprising silicate hydrates andaluminum hydrates or after coating the surface of the powder with thesilicone oil, it is extremely difficult to pulverize the titanium oxideultrafine particles to the size of the primary particles, because thetitanium oxide ultrafine particles are aggregated showing a largeparticle diameter, so that the transparency and the ultravioletshielding ability of the above obtained powder are lowered. Also, sincefresh, uncoated surfaces appear after the pulverization process iscarried out, the water-repellent ability or the oil-repellent ability ofthese surfaces is undesirably lowered. Such technological problems arisein maintaining the dispersibility of the ultrafine particles stable.Therefore, it is increasingly important to find a way to achieve a highdispersibility of the ultrafine particles and maintain it at that level.

Also, for the purposes of providing cosmetics comprising ultrafineparticles wherein the ultrafine particles are easily and uniformlydispersed and the problem of the difficult handling of the ultrafineparticles powder is eliminated, starting materials for cosmeticscomprising metal oxide ultrafine particles having a particle diameter ofnot more than 0.1 μm, a dispersion medium, and a dispersant, wherein thecontent of the ultrafine particles is not less than 10% by weight, havebeen known (Japanese Patent Laid-Open No. 6-239728) However, althoughthe problems regarding the aggregation of the ultrafine particles andthe deterioration of the dispersant, the dispersion medium, andcosmetics base materials caused by the catalytic activity of the metaloxide ultrafine particles have been known, they have neither beenaddressed nor solved in this publication. Moreover, the content of themetal oxide ultrafine particles in the starting materials for cosmeticsis limited to not less than 10% by weight in order to control theamounts in the overall cosmetics in this publication. However, as longas the metal oxide ultrafine particles are uniformly and stablydispersed, the function of the metal oxide ultrafine particles is high,and the content of the metal oxide ultrafine particles needs not belimited to a minimum amount of 10% by weight in the starting materialsfor any kind of cosmetics.

Therefore, in order not to lower the ultraviolet scattering ability bythe aggregation of the inorganic ultrafine particles, composites of theinorganic ultrafine particles are often formed with other relativelylarge carrier particles. For example, a thin flaky material dispersedwith metal compound fine particles is known (Japanese Patent Laid-OpenNo. 63-126818). However, this publication does not disclose a specificconstruction of the fine particles for improving both the shieldingability in the ultraviolet light region and the transparency in thevisible light region

Furthermore, composite fine particles comprising ultrafine particlesdispersed in and supported by the solid material are proposed.Conventional ultraviolet shielding composite fine particles include, forexample, a composite powder in which a fine particle powder, such asTiO₂, is uniformly dispersed in plate particles of metal oxides, such asSiO₂ (Japanese Patent Laid-Open No. 1-143821); and composite particlesin which a zirconium oxide powder or an aluminum oxide powder is carriedon a surface of the matrix particles comprising such materials as nylonresins, silicone resins, and silicon oxide, and a titanium oxide powderor a zinc oxide powder dispersed in an inner portion of the matrixparticles (Japanese Patent Laid-Open No. 2-49717).

However, in order to use the above composite particles as ultravioletshielding agents, the composite particles are usually dispersed in amedium in the actual environment. In this case, since the metal oxides,such as titanium oxide, contained in the composite particles havecatalytic activity, the deterioration of the medium is likely to takeplace. Also, when the difference between the refractive index of thecomposite particles and that of the medium is large, light scatteringtakes place at an interface of the composite particles and the medium,thereby making both the transparency in the visible light region and theshielding ability in the ultraviolet light region poor. Although theseproblems need to be solved, they have not been considered in the abovepublications.

In order to suppress the catalytic activities of the ultrafineparticles, methods for coating a surface of the ultrafine particles withvarious materials have been used. For example, Japanese Patent Laid-OpenNo. 5-70331 discloses the preparation of cosmetics comprising fineparticle powder wherein a basic compound and at least one of ahydrocarbon compound having a boiling point of from 100 to 200° C. and asilicone having a particular molecular structure are added during theproduction of titanium hydroxide which is obtainable by hydrolysis of atitanium alkoxide. However, in order to produce titanium hydroxide fineparticle powder, the production process must comprise drying andpulverization processes, which results in a large particle diameter ofthe obtained titanium hydroxide fine particles. Thus, it is difficultfor the particles to be highly effective in scattering ultraviolet lightB (light wavelengths of from 280 to 320 nm), while maintaining hightransparency of in the visible light region.

Also, the above publication has neither considered nor disclosed anymethod for producing ultrafine particles for the titanium hydroxideparticles or methods for dispersing the ultrafine titanium hydroxideparticles in cosmetics, in order to satisfy both high transparency inthe visible light region and high shielding ability to the ultravioletlight. Moreover, in the ultraviolet shielding materials disclosed inthis publication, titanium hydroxide or titanium oxide presumablyabsorbs the ultraviolet light B (light wavelengths of from 280 to 320nm). This ultraviolet light B only penetrates the epidermis and arelatively upper layer of the dermis, causing sunburn or skin cancers.However, titanium hydroxide or titanium oxide does not at all absorb,light having wavelengths of from 350 to 400 nm, which are closer tothose of the visible light of the ultraviolet light A (light wavelengthsof from 320 to 400 nm). The ultraviolet light A reaches skin layersbeyond the dermis, and produces suntan or fibrous modifications in thedermis. In other words, the ultraviolet absorbents disclosed in thispublication mainly exhibit absorption of the ultraviolet light B bytitanium hydroxide or titanium oxide, but their ultraviolet absorptioneffects are limited to a light wavelength of up to about 300 nm for ananatase-type titanium oxide and to a light wavelength of up to about 320nm for a rutile-type titanium oxide.

Of the ultraviolet light reaching the earth, the energy proportion ofthe ultraviolet light A is about 15 times that of the ultraviolet lightB. Therefore, in view of the above energy proportion of the ultravioletlights A and B, it is important to shield both the ultraviolet light Aas well as the ultraviolet light B, and simply shielding the ultravioletlight B is not sufficient. Moreover, it is becoming increasinglyimportant to shield both the ultraviolet light B and the ultravioletlight A, while maintaining a high transparency in the visible lightregion. In particular, in the case where the ultraviolet light A isshielded, it is important to shield light wavelengths of from 350 to 400nm, which are closer to light wavelengths of the visible light.

As mentioned above, in order to achieve an effective shielding abilityin the ultraviolet light region which maintaining and high transparencyin the visible light region, the ultraviolet shielding materials aremade ultrafine so that they are present in a highly dispersed state. Inorder to further improve the transparency in the visible light region,it is important for the difference between the refractive indices of theultraviolet shielding materials and those of surrounding media to bekept small. As the refractive index of the titania-containing compositepowders disclosed in Japanese Patent Laid-Open Nos. 1-143821 and6-116119 is limited to certain ranges determined by the compositionalratios of the components, the number of suitable dispersion media whoserefractive index corresponds to the refractive index of the compositepowder is inevitably limited as well. Therefore, great problems havebeen encountered in controlling the refractive index of the compositepowder so as to match it with the refractive index of the dispersionmedium used. Therefore, an effective means for solving these problems isin great demand.

Further, Japanese Patent Laid-Open No. 4-65312 is concerned with metalcompound-containing porous silica bead, the production method thereof,and the powder deodorant produced. In this publication, the fineparticles of the metal compounds having a primary particle diameter offrom 0.001 to 0.3 μm are contained in the porous silica bead in anamount of from 0.1 to 30% by weight, and the porous silica bead containsubstantially no voids of not less than 0.3 μm. In this case, when thefine particles of the metal compounds contained therein are suitablyselected so as to have a refractive index close to the refractive indexof silica (the refractive index being in the range of from 1.4 to 2.0),silica particles with further improved transparency can be obtained.However, the publication only discloses the range for the refractiveindex of the metal compound fine particles contained in the innerportion of the composite particles, but none of the total refractiveindex of the composite particles.

As explained above, in order to solve the problems inherent in theultraviolet shielding agents comprising the ultrafine particles, severalattempts have been made to use composites mainly comprising metaloxides. However, many of the compounds exhibiting good ultravioletabsorption properties, such as TiO₂ and ZnO, have relatively highrefractive indices, so that the composite fine particles incorporatingthese ultrafine particles have refractive indices notably higher thanaqueous solutions, conventional organic solvents, polymers, etc. Whenthe above composite fine particles are dispersed in a medium, thepresent inventors have found that light scattering in the visible lightregion takes place at the interface of the composite fine particles andthe medium, whereby the transparency of the medium is drasticallylowered. However, a technical method of controlling the refractive indexof the ultraviolet shielding particle of the composite fine particleshas not been proposed so far.

In the fields of resin fillers, fluorine-based inorganic compounds, suchas MgF₂ and CaF₂, or fluorine-based organic polymeric compounds, such aspolyethylene tetrafluoride, which are known as low-refractive indexmaterials having high transparency, are added to powders, etc. asstarting materials to lower their refractive indices.

For instance, Japanese Patent Laid-Open No. 4-85346 discloses a glasspowder, used as a transparent inorganic powder for resin fillers,comprising metal oxides, such as SiO₂, Al₂ O₃, B₂ O₃, BaO, SrO, ZnO, andMgO, and metal fluorides, the glass powder having a refractive index(n_(D)) adjusted in the range of from 1.44 to 1.70. The publicationdiscloses that since the glass powder has a high light transmittance anddoes not show strong alkalinity, the resins do not undergo anysubstantial modification, and are significantly stabilized in resinhardening. However, the publication merely discloses that a highlytransparent inorganic powder for resin fillers is obtainable by changingthe compositional ratio of the materials, and the above metal oxides,etc. are not present as particles in the final product powder owing tothe high-temperature melting production, and this publication does notrefer to the ultraviolet shielding ability. Further, this publicationdoes not disclose that the composite fine particles comprise aggregatesof two or more kinds of fine particles as in the present invention orthat the composite fine particles have the compositional dependency withrespect to an average refractive index of the composite fine particles.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide ultraviolet shieldingcomposite fine particles having substantially no catalytic activities,being uniformly and stably dispersed in a medium (for example, cosmeticsand paints), having a high transparency in the visible light region andhigh shielding ability in the ultraviolet light region, and permittingeasy handling.

Another object of the present invention is to provide a method ofproducing such ultraviolet shielding composite fine particles.

A further object of the present invention is to provide cosmeticscontaining such ultraviolet shielding composite fine particles.

These objects have been achieved by finding a high performance of theinorganic ultraviolet shielding agent in the composite fine particlescomprising daughter particles having a good ultraviolet shieldingability (i.e., ultraviolet scattering ability and absorption ability)and matrix particles in which the daughter particles are dispersed andby which the daughter particles are supported, the matrix particleshaving the high dispersibility of the daughter particles Also, thepresent inventors have found that the advantageous effects of theultrafine particles can be optimally achieved by a suitable combinationof the matrix particles and the daughter particles based on thedifference in their band gap energies.

Also, in the control of the refractive index of the composite fineparticles which can be achieved by a suitable combination of the matrixparticles containing metal oxides and low-refractive index fluorinecompounds and the daughter particles, the present inventors have foundthat in the case where the refractive index of the composite fineparticles is substantially equal to the refractive index of the medium,light scattering is well-restricted at the interface of the compositefine particles and the medium. In this case, regardless of whether theshape of the composite fine particles is spherical, plate-like, oracicular, and regardless of the surface roughness of the composite fineparticles, the light can be well transmitted into the inner portion ofthe composite fine particles. Therefore, the transparency in the visiblelight region is remarkably improved, and a high shielding ability in theultraviolet light region is achieved on account of the ultrafineparticles dispersed in the inner portion of the composite fineparticles. Also, the present inventors have found that when fineparticles having a low refractive index and a particle diameter of notmore than 0.3 μm are used, the total refractive index of the compositefine particles can be lowered without causing scattering of the visiblelight even when a fine particle size area is formed in the inner portionof the composite fine particles.

Also, the present inventors have found that the catalytic activities ofthe ultraviolet shielding composite fine particles can be substantiallysuppressed by coating a surface of the composite fine particles with aninorganic material having substantially no catalytic activities.

Furthermore, the present inventors have found that powders of compositefine particles are obtainable by subjecting the surface of the compositefine particles coated with the inorganic material having substantiallyno catalytic activities to a water-repellent treatment and pulverizingthe treated composite fine particles, and that the ultraviolet shieldingcomposite fine particles with easy handling are obtainable by subjectingthe surface of the composite fine particles to a water-repellenttreatment, and then dispersing the so treated composite fine particlesin an oil agent.

Accordingly, an aspect of the present invention is as follows:

(1) Ultraviolet shielding composite fine particles having transparencyin a visible light region, comprising:

(a) matrix particles comprising an aggregate of primary particles havingan average particle diameter of from 0.001 to 0.3 μm, the aggregatebeing formed, while the primary particles retain their shapes; and

(b) daughter particles having an average particle diameter of from 0.001to 0.1 μm, the daughter particles being dispersed in and supported bythe matrix particles, wherein the daughter particles have a smaller bandgap energy than the particles constituting the matrix particles and arecapable of absorbing ultraviolet light, and wherein the ultravioletshielding composite fine particles have substantially no catalyticactivities;

(2) The ultraviolet shielding composite fine particles described in item(1) above, wherein the surface of the ultraviolet shielding compositefine particles is coated with an inorganic material having substantiallyno catalytic activities;

(3) The ultraviolet shielding composite fine particles described in item(1) or item (2) above, wherein the particles constituting the matrixparticles have a band gap energy of from 3 to 9 eV;

(4) The ultraviolet shielding composite fine particles described in anyone of items (1) to (3) above, wherein the difference between the bandgap energies of the daughter particles and the particles constitutingthe matrix particles is not less than 0.2 eV;

(5) The ultraviolet shielding composite fine particles described in anyone items (1) to (4) above, wherein the daughter particles are dispersedin and supported by the matrix particles in an amount of from 0.1 to 85%by volume;

(6) The ultraviolet shielding composite fine particles described in anyone of items (1) to (5) above, wherein the average particle diameter ofthe ultraviolet shielding composite fine particles is not more than 0.5μm;

(7) The ultraviolet shielding composite fine particles described in anyone of items (1) to (6) above, wherein the average refractive index ofthe ultraviolet shielding composite fine particles is from 1.3 to 2.5;

(8) The ultraviolet shielding composite fine particles described in anyone of items (1) to (7) above, wherein the particles constituting thematrix particles are selected from the group consisting of metal oxides,fluorine compounds, and mixtures thereof;

(9) The ultraviolet shielding composite fine particles described in item(8) above, wherein the metal oxide is selected from the group consistingof SiO₂, Al₂ O₃, and a mixture thereof;

(10) The ultraviolet shielding composite fine particles described in anyone of items (1) to (9) above, wherein the daughter particles areselected from the group consisting of TiO₂, ZnO, CeO₂, SiC, SnO₂, WO₃,BaTiO₃, CaTiO₃, SrTiO₃, and mixtures thereof;

(11) The ultraviolet shielding composite fine particles described in anyone of items (2) to (10) above, wherein the inorganic material is ametal oxide;

(12) The ultraviolet shielding composite fine particles described initem (11) above, wherein the metal oxide used for the inorganic materialis selected from the group consisting of SiO₂, Al₂ O₃, and a mixturethereof;

(13) The ultraviolet shielding composite fine particles described in anyone of items (1) to (12), wherein the surface of the composite fineparticles is further treated by a water-repellant;

(14) The ultraviolet shielding composite fine particles described in anyone of items (1) to (13), wherein the ultraviolet shielding compositefine particles have a light transmittance of not less than 80% at awavelength of 800 nm, a light transmittance of not less than 20% at awavelength of 400 nm, and a light transmittance of not more than 5% atleast at one wavelength within the range from 380 nm to 300 nm, thelight transmittance being determined by suspending the composite fineparticles in a medium having substantially the same refractive indexlevel as the composite fine particles, and measuring with anultraviolet-visible light spectrophotometer using an optical cell havingan optical path length of 1 mm;

(15) The ultraviolet shielding composite fine particles described in anyone of items (1) to (14), obtainable by the steps of:

(a) preparing a liquid mixture comprising:

(i) starting materials for matrix particles which are present in one ormore forms selected from the group consisting of sols containingparticles constituting matrix particles and powders of the matrixparticles, the matrix particles having a primary particle with anaverage particle diameter of from 0.001 to 0.3 μm; and

(ii) starting materials for daughter particles which are present in oneor more forms selected from the group consisting of sols containingdaughter particles and powders of the daughter particles, the daughterparticles having a primary particle with an average particle diameter offrom 0.001 to 0.1 μm, and treating the liquid mixture in a mill and/oran apparatus for high-pressure dispersion, to thereby produce compositefine particles wherein the daughter particles and the matrix particlesare aggregated;

(b) coating the composite fine particles obtained in step (a) with aninorganic material;

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and

(d) drying and/or pulverizing the composite fine particles subjected tothe water-repellent treatment obtained in step (c);

(16) A dispersion oil agent of the ultraviolet shielding composite fineparticles as defined in any one of items (1) to (14) above, obtainableby the steps of:

(a) preparing a liquid mixture comprising:

(i) starting materials for matrix particles which are present in one ormore forms selected from the group consisting of sols containingparticles constituting matrix particles and powders of the matrixparticles, the matrix particles having a primary particle with anaverage particle diameter of from 0.001 to 0.3 μm; and

(ii) starting materials for daughter particles which are present in oneor more forms selected from the group consisting of sols containingdaughter particles and powders of the daughter particles, the daughterparticles having a primary particle with an average particle diameter offrom 0.001 to 0.1 μm, and treating the liquid mixture in a mill and/oran apparatus for high-pressure dispersion, to thereby produce compositefine particles wherein the daughter particles and the matrix particlesare aggregated;

(b) coating the composite fine particles obtained in step (a) with aninorganic material;

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and

(d') dispersing in an oil agent the composite fine particles subjectedto the water-repellent treatment obtained in step (c);

(17) A method for producing the ultraviolet shielding composite fineparticles comprising daughter particles being dispersed in and supportedby the matrix particles, the ultraviolet shielding composite fineparticles having substantially no catalytic activities and transparencyin a visible light region, obtainable by the steps of:

(a) preparing a liquid mixture comprising (i) starting materials formatrix particles which are present in one or more forms selected fromthe group consisting of sols containing particles constituting matrixparticles and powders of the matrix particles, the matrix particleshaving a primary particle with an average particle diameter of from0.001 to 0.3 μm; and (ii) starting materials for daughter particleswhich are present in one or more forms selected from the groupconsisting of sols containing daughter particles and powders of thedaughter particles, the daughter particles having a primary particlewith an average particle diameter of from 0.001 to 0.1 μm, and treatingthe liquid mixture in a mill and/or an apparatus for high-pressuredispersion, to thereby produce composite fine particles wherein thedaughter particles and the matrix particles are aggregated; and

(b) coating the composite fine particles obtained in step (a) with aninorganic material;

(18) The method described in item (17) above, further comprising,subsequent to step (b) above:

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment;

(19) The method described in item (18) above, further comprising,subsequent to step (c) above:

(d) drying and/or pulverizing the composite fine particles subjected tothe water-repellent treatment obtained in step (c);

(20) A method for producing the dispersion oil agent of the ultravioletshielding composite fine particles comprising daughter particles beingdispersed in and supported by the matrix particles, the ultravioletshielding composite fine particles having substantially no catalyticactivities and transparency in a visible light region, obtainable by thesteps of:

(a) preparing a liquid mixture comprising (i) starting materials formatrix particles which are present in one or more forms selected fromthe group consisting of sols containing particles constituting matrixparticles and powders of the matrix particles, the matrix particleshaving a primary particle with an average particle diameter of from0.001 to 0.3 μm; and (ii) starting materials for daughter particleswhich are present in one or more forms selected from the groupconsisting of sols containing daughter particles and powders of thedaughter particles, the daughter particles having a primary particlewith an average particle diameter of from 0.001 to 0.1 μm, and treatingthe liquid mixture in a mill and/or an apparatus for high-pressuredispersion, to thereby produce composite fine particles wherein thedaughter particles and the matrix particles are aggregated;

(b) coating the composite fine particles obtained in step (a) with aninorganic material;

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and

(d') dispersing in an oil agent the composite fine particles subjectedto the water-repellent treatment obtained in step (c);

(21) Cosmetics comprising ultraviolet shielding composite fine particlesas defined in any one of items (1) to (15) above;

(22) Cosmetics comprising the dispersion oil agent of the ultravioletshielding composite fine particles as defined in item (16);

(23) The cosmetics described in any one of items (18) to (21) above,wherein the amount of the ultraviolet shielding composite fine particlesis from 0.1 to 50% by weight;

(24) The cosmetics described in any one of items (21) to (23) above,further containing an ultraviolet protecting agent;

(25) The cosmetics described in any one of items (21) to (24) above,wherein SPF measured by using an analyzer "SPF-290," manufactured by TheOptometrics Group is not less than 8, and wherein ΔE*ab before and afterskin application is not more than 3 as defined according to JIS z8729-1980; and

(26) The use of the ultraviolet shielding composite fine particles asdefined in any one of items (1) to (15) as cosmetics.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are notlimitative of the present invention, and wherein:

FIG. 1 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 1, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 2 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 2, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 3 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 3, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 4 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 4, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 5 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 5, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 6 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 6, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 7 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 7, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 8 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 8, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 9 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 9, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 10 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 10, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 11 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 11, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 12 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 12, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 13 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 13, as measured by an ultraviolet-visiblelight spectrophotometer;

FIG. 14 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 14, as measured by an ultraviolet-visiblelight spectrophotometer; and

FIG. 15 is a graph showing the relationship between light wavelength andlight transmittance of the ultraviolet shielding composite fineparticles obtained in Example 15, as measured by an ultraviolet-visiblelight spectrophotometer.

BEST MODE FOR CARRYING OUT THE INVENTION

Fine particles having a relatively small particle diameter and having ahigh shielding ability against ultraviolet light are likely to formaggregates, so that when dispersed in a medium the fine particles wouldnot perform their shielding function well. Therefore, by the formationof a composite of the fine particles with relative large particles,namely by supporting the fine particles as daughter particles in matrixparticles used as a carrier, the fine particles are maintained in a gooddispersion state, thereby retaining their high shielding ability againstthe ultraviolet light. Further, by coating the surface of the compositefine particles with an inorganic material having substantially nocatalytic activities, the catalytic activities of the composite fineparticles can be substantially suppressed. Therefore, by coating thesurface of the composite fine particles with an inorganic materialhaving substantially no catalytic activities, even when the compositefine particles are subjected to a surface-improvement treatment, thetreatment material used is not likely to undergo deterioration bycatalytic activities or photo-catalytic activities of the composite fineparticles.

Furthermore, ultraviolet shielding composite fine particles having easyhandling are obtainable by the steps of subjecting the surface of thecomposite fine particles coated with an inorganic material to awater-repellent treatment, and then pulverizing the composite fineparticles obtained after the water-repellent treatment to give a powder.Alternatively, the ultraviolet shielding composite fine particles arealso obtainable by the steps of subjecting the surface of the compositefine particles to a water-repellent treatment, and then dispersing thecomposite fine particles in an oil agent. In the present specification,the matrix particles of the composite fine particles refer to a matrixcapable of containing and supporting daughter particles dispersedtherein. The matrix particles are aggregates formed while retaining theshapes of the particles constituting the matrix particles (i.e., primaryparticles). The daughter particles refer to particles other than thematrix particles having an ultraviolet shielding ability.

1. Preferred embodiments of the present invention will be explained indetail below by referring to the following properties of the compositefine particles: (1) band gap energy of the particles, (2) refractiveindex of the composite fine particles, (3) grain boundaries of theparticles, and (4) coatings formed on the surface of the composite fineparticles by inorganic materials

(1) Band Gap Energy of Particles

In the composite fine particles of the present invention, the fineparticles used as the daughter particles have to have a good shieldingability against ultraviolet light. The ultraviolet shielding abilitiesare classified into two kinds: Absorbing ability of ultraviolet lightand scattering ability of ultraviolet light.

The ultraviolet light absorption by inorganic compounds is ascribed toexciton absorption of mainly semiconductive compounds, and compoundshaving a band gap energy of from 3.0 to 4.0 eV effectively show such aproperty. Scattering of ultraviolet light is strongly exhibited as Miescattering. In the case of high-refractive index materials, such asTiO₂, scattering is remarkably observed when the particle diameter ofthe material is about one-half the wavelength of the ultraviolet light,namely not more than 0.2 μm.

Since in ceramics the valence electron band and the conduction band arenot continuous, ceramics are known to absorb light having a wavelengthcorresponding to an energy not less than the band gap energy, the bandgap energy referring to the difference between the energy level of thevalence electron band and that of the conduction band. For instance, ZnOhas a band gap energy of 3.2 eV, which absorbs light having a wavelengthof not more than 390 nm. The inorganic ultraviolet shielding agentabsorbs ultraviolet light because its band gap energy corresponds to thewavelength of the ultraviolet light

Therefore, in the composite fine particles of the present invention, inorder for the daughter particles to exhibit effective scattering abilityand absorption ability of ultraviolet light, the particles constitutingthe matrix particles must have a band gap energy larger than that of thedaughter particles. For instance, in the case of using aggregates ofTiO₂ particles (rutile-type) as the matrix particles, and ZnO fineparticles having a band gap energy smaller than that of TiO₂ as thedaughter particles, the ultraviolet light having a wavelength of notmore than 320 nm is absorbed by exciton absorption corresponding to theband gap energy of the particles constituting the matrix particles,namely TiO₂. Also, ultraviolet light having a wavelength in the vicinityof 350 nm, which penetrates the matrix particles without being absorbed,is absorbed by exciton absorption corresponding to the band gap energyof the daughter particles while being multiply scattered by the daughterparticles Accordingly, the ZnO/TiO₂ (daughter/matrix) composite fineparticles have a shielding ability against ultraviolet light having awavelength of not more than 350 nm.

By contrast, when TiO₂ is used as the particles constituting the matrixparticles and SnO₂ fine particles having a larger band gap energy thanTiO₂ is used as the daughter particles, the ultraviolet light having awavelength of not more than 320 nm is absorbed by exciton absorptioncorresponding to the band gap energy of the TiO₂ particles. However, theultraviolet light having a wavelength in the vicinity of 350 nm, whichpenetrates the matrix particles without being absorbed, is not absorbedby exciton absorption corresponding to a band gap energy of SnO₂.Accordingly, the SnO₂ /TiO₂ (daughter/matrix) composite fine particlescannot provide sufficient shielding effects against ultraviolet lighthaving wavelengths in the vicinity of 350 nm.

For the above reasons, in the composite fine particles of the presentinvention, the particles constituting the matrix particles have a bandgap energy of preferably 3 to 9 eV, more preferably 5 to 9eV. In orderto more securely have the ultraviolet light reach the daughterparticles, the difference between the minimum band gap energy of thedaughter particles and the band gap energy of the particles constitutingthe matrix particles is preferably not less than 0.2 eV, the ultravioletlight having wavelengths at which absorption and scattering of theultraviolet light can be achieved by the daughter particles.

(2) Refractive Indices of Composite Fine Particles

When the ultraviolet shielding composite fine particles are actuallyused, it is necessary for them to exhibit high transparency in thevisible light region while maintaining a high shielding ability in theultraviolet light region. Here, (i) in order to maintain a highshielding ability, the difference between the refractive indices of thematrix particles and the daughter particles has to be kept as large aspossible because the ultraviolet shielding ability is remarkablyimproved when the difference between the refractive indices is keptlarge. In the present invention, the difference between the refractiveindices is preferably not less than 0.1. For this reason, in the presentinvention, metal oxides and fluorine compounds both having relativelylow-refractive indices are used as materials constituting the matrixparticles together with the daughter particles having a relatively highrefractive index. Also, (ii) in order to exhibit high transparency, thedifference between the refractive indices of the composite fineparticles and the surrounding materials (medium) has to be kept as smallas possible. Thus, the refractive index of the composite fine particleshas to be controlled in order to make the difference small. The presentinvention is characterized by adjusting the refractive indices of thecomposite fine particles by controlling the volume ratios between thematrix particles and the daughter particles, and further by using afluorine compound.

In a suspension of the composite fine particles, such as a suspension tobe used for cosmetics, etc., when the refractive index of the compositefine-particles differs largely from that of the medium, transparency islikely to be lost because the visible light is refracted or reflected atthe interface of the composite fine particles and the medium. Here, therefractive index may be measured by a generally known immersion method(see Toshiharu Takou, et al., Optical Measurement Handbook, p. 475,1981, published by Asakura Publishers). In this method, the refractiveindex of the sample is the refractive index of a medium, whose highestlight transmittance is obtained at a wavelength of 589.3 nm. However,the operating procedure for the immersion method is complicated, andtime-consuming. For convenience, the refractive index can betheoretically calculated from the refractive indices of the daughterparticles and the primary particles of the matrix particles and thevolume ratio therebetween. Since the theoretically calculated refractiveindex closely approximates data obtained by the immersion methoddepending on the composite fine particles, the refractive indices of thecomposite fine particles can be also obtained by a simple calculationmethod as mentioned above.

The refractive index n_(D) ²⁰ of the generally used medium is from 1.3to 1.8. On the other hand, since many of metal oxides having a highultraviolet shielding ability, such as TiO₂ and ZnO, have a refractiveindex n_(D) ²⁰ of not less than 2.0, when the metal oxides are used asthe daughter particles, the refractive index of the composite fineparticles has to be approximated to that of the medium by using alow-refractive index material for the matrix particles. Specifically, anaverage refractive index of the composite fine particles is from 1.3 to2.5, preferably from 1.3 to 2.0, more preferably from 1.3 to 1.8,particularly preferably from 1.3 to 1.7, and most preferably from 1.4 to1.5. Also, a difference of the refractive indices between the matrixparticles and the daughter particles in the composite fine particles ofthe present invention is preferably not less than 0.1. By keeping thedifference between the refractive indices, the scattering ability of theultraviolet light is improved.

(3) Grain Boundaries of Particles

As the particle diameter of the primary particles of the matrixparticles becomes smaller, namely as the grain boundaries in the innerportion of the matrix particles become smaller, the visible light cannotdetect the presence of the grain boundaries, so that the matrixparticles are provided with transparency regardless of whether theprimary particles of the matrix particles are crystallized. Since thedaughter particles similarly comprise ultrafine particles, they alsohave good transparency. Therefore, the composite fine particles have analtogether good transparency.

(4) Coatings Formed on the Surface of the Composite Fine Particles byInorganic Materials

In the case of coating the surface of the composite fine particles withan inorganic material having substantially no catalytic activities inorder to suppress the catalytic activities of the ultrafine particles,the formed coating layer may be either a thin layer or a thin, fineparticle layer. The thickness of the coating layer is considered to besufficient if the active sites on the surface of the composite fineparticles are substantially coated so as to prevent the surfaceactivities from affecting the surrounding medium of the composite fineparticles. In other words, by substantially suppressing the surfaceactivities of the composite fine particles, the deterioration of themedium at the surface of the composite fine particles and the mediumcontacting their surfaces, the media being, for instance, cosmetic basematerials, paints, etc., can be prevented. Also, since the dispersant isnot deteriorated, the dispersibility of the composite fine particles canbe stably maintained for a long period of time. While the above areconventionally unavoidable problems in cases where inorganic,ultraviolet shielding agents are generally dispersed in various kinds ofmedia, the present invention provides a means for solving theconventional problems.

2. Next, the method for producing the ultraviolet shielding compositefine particles of the present invention will be explained according toeach of the steps described below.

The water-repellent treatment step for the composite fine particlesindicated in the steps below is optional in the present invention.However, in cases where the obtained composite fine particles areincorporated in cosmetics, etc., the water-repellent treatment step ispreferably included. The production methods including thewater-repellent treatment step are given below as preferred embodimentsof the present invention. There are two embodiments: (1) One embodimentwhere the composite fine particles are powdered by drying andpulverization; and (2) another embodiment where the composite fineparticles are dispersed in an oil agent. Each of the embodiments (1) and(2) comprises the following steps.

(1) Embodiment Where the Composite Fine Particles are Powdered by Dryingand Pulverization

In this embodiment, the method for producing composite fine particlescomprises the steps of:

(a) preparing a liquid mixture comprising (i) starting materials formatrix particles which are present in one or more forms selected fromthe group consisting of sols containing particles constituting matrixparticles and powders of the matrix particles, the matrix particleshaving a primary particle with an average particle diameter of from0.001 to 0.3 μm; and (ii) starting materials for daughter particleswhich are present in one or more forms selected from the groupconsisting of sols containing daughter particles and powders of thedaughter particles, the daughter particles having a primary particlewith an average particle diameter of from 0.001 to 0.1 μm, and treatingthe liquid mixture in a mill and/or an apparatus for high-pressuredispersion, to thereby produce composite fine particles wherein thedaughter particles and the matrix particles are aggregated; and

(b) coating the composite fine particles obtained in step (a) with aninorganic material.

In this embodiment, the following additional steps may be carried out.

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and

(d) drying and/or pulverizing the composite fine particles subjected tothe water-repellent treatment obtained in step (c).

(2) Embodiment Where the Composite Fine Particles are Dispersed in anOil Agent.

In this embodiment, the method for producing composite fine particlescomprises the steps of:

(a) preparing a liquid mixture comprising (i) starting materials formatrix particles which are present in one or more forms selected fromthe group consisting of sols containing particles constituting matrixparticles and powders of the matrix particles, the matrix particleshaving a primary particle with an average particle diameter of from0.001 to 0.3 μm; and (ii) starting materials for daughter particleswhich are present in one or more forms selected from the groupconsisting of sols containing daughter particles and powders of thedaughter particles, the daughter particles having a primary particlewith an average particle diameter of from 0.001 to 0.1 μm, and treatingthe liquid mixture in a mill and/or an apparatus for high-pressuredispersion, to thereby produce composite fine particles wherein thedaughter particles and the matrix particles are aggregated;

(b) coating the composite fine particles obtained in step (a) with aninorganic material;

(c) subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and

(d') dispersing in an oil agent the composite fine particles subjectedto the water-repellent treatment obtained in step (c).

In the preparation of the liquid mixture in step (a) above, the powdersof the daughter particles where these particles comprise ultrafineparticles having an average particle diameter of from 0.001 to 0.1 μmare desirably disintegrated and/or pulverized in a mill or an apparatusfor high-pressure dispersion, whereby the dispersion state of thedaughter particles in the liquid mixture is maintained. Examples ofmills include bead mills, sand mills, and ball mills, and examples ofhigh-pressure dispersion devices include microfluidizers and nanomizers.

In the present invention, in the case where the daughter particlescomprising the above ultrafine particles and a liquid mixture having alarge proportion and high concentration of the daughter particles aresubjected to a mill treatment and/or a high-pressure dispersiontreatment, a pre-treatment is preferably carried out prior to the milltreatment and/or the high-pressure dispersion treatment using adispersion device capable of disintegrating powders of the ultrafineparticles, the dispersion devices including homomixers and homogenizers.The reasons for carrying out the pre-treatment are as follows. Bydisintegrating the powders of the ultrafine particles which are in anaggregated state at a high concentration, the load for thedisintegration and/or pulverization required in subsequent treatmentsfollowing the pre-treatment step, namely a mill treatment step and/or ahigh-pressure dispersion treatment step, is notably reduced, so that thedisintegration and/or pulverization are efficiently carried out, therebyresulting in a good dispersion of the ultrafine particles.

In the coating step with the inorganic materials according to step (b),the coating methods are not particularly limited, and any of the coatingmethods utilized for sol-gel reaction methods and precipitation reactionmethods can be employed. The inorganic materials to be used for coatingare not particularly limited as long as they are inorganic materialshaving substantially no catalytic activity. Among them, a preference isgiven to metal oxides, with a particular preference being given to SiO₂,Al₂ O₃, and a mixture thereof. The starting materials for the inorganicmaterials used in the coating step are not particularly limited, and anyof the metal salts, such as metal alkoxides, metal nitrates, and metalsulfates, may be used. Specific examples of the metal salts includetetraethoxysilane, aluminum isopropoxide, aluminum tri-sec-butoxide,sodium silicates, and aluminum sulfate. By utilizing the precipitationreaction and the sol-gel reaction depending upon the properties of theabove starting materials for the inorganic materials used, the surfaceof the composite fine particles can be coated with the inorganicmaterials. Incidentally, after the coating step, a neutralizationreaction step may be optionally added before or after thewater-repellent treatment step.

In the present specification, the "sol-gel reaction method" refers to amethod comprising allowing colloidal particles contained in a sol togrow by coagulation or aggregation, thereby allowing gelation of theresulting colloidal particles to take place. In the case where the abovesol-gel reaction method is utilized to coat the surface of the compositefine particles, the gelation mentioned above can be carried out on thesurface of the composite fine particles. Also, the "precipitationreaction method" refers to a method comprising adding a precipitationagent to a solution containing the metal salts, to give precipitatedparticles. In this method, concentrations, pHs, and temperatures aresuitably controlled to have the precipitated particles adhere on thesurface of the composite fine particles. Examples of the precipitationreaction methods include coprecipitation methods, methods ofprecipitation from homogeneous solution, and compound precipitationmethods.

Although the amount of the inorganic materials applied as a coating isnot particularly limited, exceedingly large amounts of coating give riseto a large diameter of the composite fine particles, thereby drasticallyimpairing the optical properties of the composite fine particles. On theother hand, too small amounts of coating lead to undesirable catalyticactivities of the composite fine particles. Therefore, the amount of theinorganic materials applied as a coating has to be suitably adjusted inorder not to cause such undesired effects.

In the water-repellent treatment according to step (c) above, thewater-repellants and the methods for water-repellent treatment are notparticularly limited, and any of the water-repellent treatment methodscan be employed, including treatments with silicone compounds, such asmethyl hydrogen polysiloxane, high-viscosity silicone oils,oxazoline-modified silicones, amino-modified silicones, and siliconeresins; treatments with surfactants, including anionic surfactants, suchas stearic acid and oleic acid, and cationic surfactants; treatmentswith macromolecular compounds, such as nylon, polymethylmethacrylate,polyethylene, Teflon™, and polyamino acids; treatments withperfluoro-group containing compounds, lecithin, collagen, metal soaps,lipophilic waxes, partial esters of polyhydric alcohols, and wholeesters of polyhydric alcohols; and treatments with phosphate compounds,such as monoalkylphosphates and dialkylphosphates, without intending tolimit the treatment methods to those listed above. In principle,electrostatic forces between the surface of the composite fine particlesand the water-repellants may be employed. Also, seed condensation of thewater-repellants containing the composite fine particles as a seed maybe employed in a water-repellent treatment methods. Incidentally, aneutralization reaction step may be optionally added before or after thewater-repellent treatment step. Although step (c) is an optional processin Embodiment (1), the coating step may be preferably carried out fromthe viewpoint of suppressing the surface activities and dispersing thecomposite fine particles.

Next, in step (d) of drying and pulverizing the composite fine particlessubjected to a water-repellent treatment, the drying methods and thepulverization methods are not particularly limited. For example, dryingmethods such as hot-air drying and topping treatments may be employed,and in the pulverization method, sand mills and blade-type mills may beemployed. The composite fine particles obtained after the pulverizationstep may be controlled to a given particle diameter by classification.In order to determine the particle diameter and shapes of the resultingcomposite fine particles or the particle diameters of the daughterparticles and the matrix particles, an electron microscope may be used.

In step (d') where the composite fine particles are dispersed in an oilagent, the methods for dispersing the composite fine particles in an oilagent are not particularly limited. For instance, after mixing the oilagent and the liquid mixture dispersion containing the composite fineparticles subjected to the water-repellent treatment, such treatments asa topping treatment may be carried out in the case where the solvent ofthe liquid mixture dispersion is volatile, as in the case of ethanol.Alternatively, after the above mixing step, conventional solventsubstitution methods may be carried out in the case where the solvent isnon-volatile. Incidentally, examples of the oil agents include varioushydrocarbons, higher fatty acids, fats and oils, esters, higheralcohols, and waxes, such as squalane, paraffin wax, liquid paraffin,Vaseline™, microcrystalline wax, ozocerite, ceresine, myristic acid,palmitic acid, stearic acid, oleic acid, isostearic acid, cetyl alcohol,hexadecyl alcohol, oleyl alcohol, cetyl 2-ethylhexanoate, 2-ethylhexylpalmitate, 2-octyldodecyl myristate, neopentyl glycoldi-2-ethylhexanoate, glycerol tri-2-ethylhexanoate, 2-octyldodecyloleate, isopropyl myristate, glycerol triisostearate, coconut fatty acidtriglyceride, olive oil, avocado oil, camellia oil, jojoba oil, beeswax,spermaceti, carnauba wax, myristyl myristate, mink oil, and lanoline;silicone oils, such as volatile silicone oils and non-volatile siliconeoils. In addition, in the case where the composite fine particlessurface-treated with a volatile material are dispersed in an oil agent,it is preferred that the moisture of the composite fine particles andthe liquid mixture dispersion be removed in order to prevent theformation of a water and oil emulsion. Suitable methods for dehydrationare reflux and topping treatments using such solvents as hexane andcyclohexane.

The concentration of the composite fine particles in the oil agent isnot particularly limited, and the concentration of the composite fineparticles dispersible in the oil agent is highly related to the particlediameters of the composite fine particles and the kinds of thewater-repellants and the oil agents used. When the concentration of thecomposite fine particles is too high, the aggregation of the compositefine particles takes place in the oil agent, thereby notablydeteriorating the dispersibility and the optical properties of thecomposite fine particles, which in turn leads to the deterioration ofthe properties of the oil agent. Therefore, the concentration of thecomposite fine particles in the oil agent has to be suitably adjusted inorder avoid undesirable effects.

3. Each of the starting materials used in the production methods of thepresent invention will be explained in detail below.

(1) Daughter Particles

The daughter particles constituting the composite fine particles in thepresent invention maintain good transparency in the visible light regionwhile having a good shielding ability in the ultraviolet light region.Therefore, the daughter particles ideally do not absorb the light in thevisible light region and to have a particle diameter small enough not toscatter the visible light.

In order to satisfy the requirements of not absorbing the visible lightand absorbing the ultraviolet light, the materials constituting thedaughter particles preferably have a wavelength for an excitonabsorption of a band gap energy corresponding to the wavelengths in theultraviolet light region. Specifically, semiconductive compounds havinga band gap energy of from 3.0 to 4.0 eV are preferred, including, forinstance, TiO₂, ZnO, CeO₂, SiC, SnO₂, WO₃, SrTiO₃, BaTiO₃, and CaTiO₃,which characteristically exhibit the above property. Among them, TiO₂,ZnO, and CeO₂ are conventionally used as ultraviolet shielding agents,and these compounds, which are particularly preferred examples, may beused singly or in combination. In particular, in order to shield theultraviolet light of the ultraviolet light region A (320 to 400 nm), ZnOand CeO₂ are effectively used. Also, in order to shield the ultravioletlight of the ultraviolet light region B (280 to 320 nm), TiO₂ iseffectively used. Incidentally, in order to shield both the ultravioletlight of the ultraviolet light region B and that of the ultravioletlight region A, the daughter particles comprising TiO₂ and one or morecompounds selected from the group consisting of ZnO, CeO₂, BaTiO₃,CaTiO₃, SrTiO₃, and SiC may be preferably used in combination.

Alternatively, in the case where TiO₂ is used, the shielding region canbe extended to the ultraviolet light region A by incorporating, asimpurity dopes, an element having a valence number of 5 or more, such asW, P, Ta, Nb, Sb, or Mo, or an element having a valence number of 3 orless, such as Zn, Al, Mg, and Ca.

The shapes of the daughter particles are not particularly limited, andmay be spherical, plate-like or acicular. The particle diameter of thedaughter particles is preferably substantially the same as that of theprimary particles of the matrix particles from the viewpoint ofproviding good dispersion of the daughter particles in the matrixparticles. Furthermore, as for the scattering ability of the light inthe ultraviolet light region, which is strongly exhibited by Miescattering, scattering can be remarkably noted when the particlediameter is about one-half the wavelength of the ultraviolet light,namely, not more than 0.2 μm. Therefore, in order to satisfy both goodtransparency in the visible light region and good shielding ability inthe ultraviolet light region, the daughter particles have an averageparticle diameter of preferably not more than 0.2 μm, more preferablynot more than 0.1 μm, particularly 0.001 to 0.1 μm, and moreparticularly not more than 0.05 μm. In the present invention, the term"daughter particles" refers to primary particles individually dispersedin and supported by the matrix particles and/or aggregates of theprimary particles. Therefore, the average particle diameter of thedaughter particles may also mean the average particle diameter of theaggregates.

In the present invention, the sols containing the daughter particles andthe daughter particle powder are used upon production for the startingmaterials for the daughter particles. Since the daughter particles arepresent preferably in a dispersed state in the inner portion of thecomposite fine particles, higher dispersibility and stability of thedaughter particles in a sol are desired. In order to achieve such statesof the daughter particles in a sol, the surface of the daughterparticles may be coated with other materials, or the daughter particlesmay be blended with a sol stabilizer. For instance, in the case whereTiO₂ ultrafine particles are used as the daughter particles, the surfaceof the ultrafine particles may be coated with such compounds as SiO₂ andAl₂ O₃ to improve dispersibility. Alternatively, the ultrafine particlesmay be blended with a basic stabilizer, such as NH₃, to stabilize thestate of the TiO₂ sol. Also, in the case where the fine particle powderis surface-treated to achieve good dispersion, the treated fineparticles can be used as starting materials for the daughter particles.The sol used in the present invention refers to fluids containingparticles which cannot be generally observed by an ordinary electronmicroscope but having a particle diameter larger than that of an atom orthat of a low molecular compound (see Iwanami Dictionary of Physics andChemistry, Third Edition, published by Iwanami Publishers). Examples ofsols include hydrosols of silica and suspensions of TiO₂ ultrafineparticles.

(2) Matrix Particles

The matrix particles constituting the composite fine particles must havegood transparency in the visible light region as must the daughterparticles in order to afford good transparency to the composite fineparticle suspension. Specifically, the matrix particles are desirablyconstituted by materials which do not absorb the visible light, and theprimary particles of the matrix particles preferably do not have aparticle diameter exceeding 0.3 μm. For instance, a preference is givento aggregates of the ultrafine particles, each of the ultrafineparticles having an average particle diameter of 0.01 μm.

As for the materials constituting the matrix particles, materials havinghigh transparency, such as metal oxides, fluorine compounds, andmixtures thereof, may be used. For instance, metal oxides, fluorinecompounds, and mixtures thereof may be used. Since the aggregates of thefine particles normally constitute the matrix particles, the fineparticles (i.e. primary particles) constituting the aggregates have anaverage particle diameter of not more than 0.3 μm, specifically, from0.001 to 0.3 μm, in order to satisfy the requirements for the matrixparticles as mentioned above. A preference is given to particles havingan average particle diameter of not more than 0.15 μm, more preferablynot more than 0.1 μm, particularly preferably not more than 0.05 μm.Sols containing particles constituting the matrix particles and matrixparticle powder are used for the starting materials for the matrixparticles. For the same reasons as mentioned in connection with thedaughter particles, the surface of the particles constituting the matrixparticles may be coated with other materials, or the fine particles maybe blended with sol stabilizers. Here, the coating materials or thestabilizers used may be similar to those used for the daughterparticles.

Many of the metal oxides are available in the form of chemically stablesolids, so that the metal oxides can be suitably used for materialsconstituting the matrix particles. Examples of the metal oxidescontained in the matrix particles include TiO₂, CuO, ZnO, MgO, CeO₂,SnO₂, SiO₂, Fe₂ O₃, Al₂ O₃, NiO₂, and MnO₂. A preference is given toSiO₂ and Al₂ O₃ because of having a suitable refractive index and goodtransparency as explained above. Also, a preference is given to fineparticles of SnO₂, In₂ O₃, SiO₂, ZnO, and Al₂ O₃ from the viewpoint ofusing ceramic fine particles having large band gap energies.

Many of the fluorine compounds are chemically stable and have a lowrefractive index, so that the compounds are highly useful forcontrolling the refractive index of the resulting composite fineparticles. The fluorine compounds include all those present in solid orliquid state at room temperature. Examples of such solid inorganicfluorine compounds include MgF₂, CaF₂, AlF₃, LiF, NiF₂, and BaF₂.Examples of solid organic fluorine compounds include fluororesins, suchas polytetrafluoroethylene (hereinafter simply abbreviated as "PTFE"), atetrafluoroethylene-hexafluoropropylene copolymer, atetrafluoroethylene-ethylene copolymer, vinylidene polyfluoride, andvinyl polyfluoride. Among them, MgF₂, polytetrafluoroethylene, and amixture thereof are suitably used as fluorine compounds because of thesuitable refractive index and good transparency of the resultingcomposite fine particles.

The average particle diameter of the fluorine compounds in solid stateat room temperature is preferably not more than 0.3 μm, more preferablynot more than 0.2 μm. The reason therefor is that when the averageparticle diameter exceeds 0.3 μm, the aggregating forces among theparticles become weak, thereby lowering the strength of the compositefine particles.

Examples of liquid fluorine compounds at room temperature includeperfluoropolyethers (hereinafter simple abbreviated as "PFPE"). Anexample of PFPE may be perfluoropolymethylisopropylether (for instance,"FOMBLIN HC", manufactured by Nikko Chemicals K.K.). PFPE is useful notonly for lowering the refractive index of the composite fine particlesbut also for providing moisture with smooth skin texture, so that thePFPE is highly suitable as fine particles for use in cosmetics. When theliquid fluorine compounds are used, the solvents used may be properlychosen in order not to cause phase separation of the daughter particlestarting materials and the matrix particle starting materials in thesolvent. However, when the solvent is water, an emulsion comprisingliquid fluorine compounds at room temperature which are emulsified byvarious kinds of surfactants may be preferably used. For instance, anemulsion of perfluoropolyether (oil-in-water type) may be used. Theemulsion diameter is preferably of a size not exceeding 0.1 times thatof droplets. When the emulsion diameter exceeds 0.1 times that of thedroplets, the emulsion becomes larger than the produced particles, andthereby the production of particles becomes difficult.

In the present invention, the liquid fluorine compounds may be also usedas materials having low refractive indices as explained above. In thiscase, the liquid fluorine compounds may be used together with the metaloxides and/or the solid fluorine compounds in order to increase freedomin the refractive index control.

Regarding suitable combinations of the daughter particles and the matrixparticles of the present invention, a preference is given to thecombinations where the daughter particles are selected from TiO₂, ZnO,and a mixture thereof; the matrix particles are selected from SiO₂, Al₂O₃, and a mixture thereof, and a mixture of SiO₂ withperfluoropolyether; inorganic material coatings are selected from SiO₂,Al₂ O₃, and a mixture thereof; and water repellants are one or morecompounds selected from methyl hydrogen polysiloxane, oxazoline-modifiedsilicones, amino-modified silicones, stearic acid, monoalkylphosphates,and dialkylphosphates, from the viewpoints of providing safety andstability of the resulting ultraviolet shielding agents

In the present invention, materials other than the metal oxides and thefluorine compounds mentioned above may be included in the daughterparticles and the matrix particles. For example, in the case where thecomposite fine particles are produced by stabilizers of the startingmaterial sol or a coating agent for sol particles, etc. may be containedin the matrix particles as long as the optical properties of thecomposite fine particles are not impaired.

4. The preparation of the starting material liquid mixture using thestarting materials mentioned above and the method for producing thecomposite fine particles will be explained in more detail below.

When the liquid mixture of the starting materials is prepared, it isimportant to uniformly disperse and blend the liquid mixture containingthe starting materials for the daughter particles and the startingmaterials for the matrix particles, so as to easily disperse thedaughter particles in the matrix particles. By thoroughly blending thestarting materials for the daughter particles and the starting materialsfor the matrix particles to achieve a high dispersion of the daughterparticles in the matrix particles, the daughter particles can be presenton the surface of and/or in the inner portions of the matrix particles.At this time, fine particles comprising starting materials of daughterparticles and those of matrix particles are gathered by electrostaticforces, to give aggregated composite fine particles.

For instance, in the case where TiO₂ ultrafine particle powder is usedas the starting material for the daughter particles and an SiO₂ sol(aqueous; "ST-C," manufactured by Nissan Chemical Industries, Ltd.; pH8.5 to 9.0) is used as the starting materials for the matrix particles,and the above starting materials are subjected to a treatment in a millor a high-pressure dispersion device at appropriate conditions and thepH of the resulting liquid mixture is adjusted to 7, TiO₂ with anisoelectric point of pH of about 5 to 7 is negatively charged on accountof its isoelectric point, and SiO₂ forms an electric double layer whosesurface is positively charged, so that composite fine particles areformed by aggregation of the daughter particles and the matrix particlesby electrostatic forces generated between the TiO₂ daughter particlesand the SiO₂ matrix particles. Also, in another case where ZnO ultrafineparticle powder is used as the starting material for the daughterparticles and an SiO₂ sol (aqueous; "ST-C," manufactured by NissanChemical Industries, Ltd.; pH 8.5 to 9.0) is used as the startingmaterials for the matrix particles, and where the above startingmaterials are subjected to a treatment in a mill or a high-pressuredispersion device at appropriate conditions while the pH of theresulting liquid mixture is adjusted to 7, ZnO with an isoelectric pointof pH of about 9.3 is positively charged on account of its isoelectricpoint, and SiO₂ forms an electric double layer whose surface ispositively charged. Observations made by a transmission electronmicroscope resulted in the finding that composite fine particles areformed by aggregation of ZnO daughter particles and SiO₂ matrixparticles. Incidentally, when the composite fine particles are formed, aslidable surface in the electric double layer of SiO₂ is presumablycracked whereby the surface is negatively charged, and the negativelycharged surface contacts the ZnO daughter particles.

The SiO₂ sols which are used in the above examples have the followingfunctions:

(1) they act as a medium for efficiently disintegrating daughterparticles which are normally present in an aggregated state to about thesize of the particle diameter of the primary particles and/or as amedium for pulverizing the daughter particles to a size not greater theparticle diameter of the primary particles;

(2) they form a basic structure in which the daughter particles adhereto the matrix particles simultaneously with the disintegration and/orpulverization; and

(3) they act as a dispersant for inhibiting the aggregation of thecomposite fine particles with each other by electrostatic repulsion ofSiO₂ on the surface of the composite fine particles after formation ofthe composite fine particles.

The particle diameter of the SiO₂ sol may be suitably chosen accordingto functions (1) to (3) described above. For instance, in the case wherefunction (3) is considered to be very important, the particle diameterof the SiO₂ sol is preferably about the same size as or less than theparticle diameter of the daughter particles. Specifically, the particlediameter of the SiO₂ sol is suitably not more than 0.1 μm, preferablynot more than 0.05 μm, more preferably not more than 0.02 μm.Incidentally, the solvents used for the SiO₂ sol include hydrosols(aqueous) and organosols, which may be suitably selected taking intoconsideration the kinds of the daughter particles and the dispersionstability.

According to the methods described above, the composite fine particlescomprising aggregates of the daughter particles and the matrix particlesare formed, and in order to firmly maintain the aggregated state of thecomposite fine particles and to have substantially no catalyticactivities by the daughter particles, the surface of the composite fineparticles is coated with the inorganic materials having substantially nocatalytic activities. As explained above, the coating layer may beeither a thin layer or a thin, fine particle layer. As for the thicknessof the coating layer, thickness is considered to be sufficient if theactive sites on the surface of the composite fine particles aresubstantially coated so as not to have the surface actions affect thesurrounding medium of the composite fine particles.

Suitable solvents for the starting materials for the daughter particlesand the starting materials for the matrix particles mentioned above areany aqueous or organic solvents, which do not inhibit the production ofthe composite fine particles comprising the daughter particles/matrixparticles composite in the starting material liquid mixture. Examples ofthe organic solvents include alcohols, such as methanol and ethanol, andpolar solvents, such as N,N-dimethylformamide, dimethyl sulfoxide,hexamethylphosphoramide, and ethyl acetate. As long as the formation ofthe ultraviolet shielding composite fine particles is not adverselyaffected, the solvents for the metal oxide sol solutions mentioned aboveor different ones may be used.

The concentration of the starting materials for the matrix particles inthe starting material liquid mixture containing the starting materialsfor the daughter particles and the starting materials for the matrixparticles is preferably in the range of from 10⁻⁵ to 10 mol/L, morepreferably from 10⁻⁴ to 1 mol/L. Specifically, the concentration of thestarting materials for the matrix particles is preferably not less than10⁻⁵ mol/L, from the viewpoint of maintaining the daughter particleswell dispersed in the composite fine particles, and the concentration ispreferably not more than 10 mol/L, from the viewpoint of maintaining thestarting material of the matrix particles and the daughter particleswell dispersed in the starting material liquid mixture.

When a fluorine compound is used as a starting material for the matrixparticles, the concentration of the fluorine compound in the startingmaterial liquid mixture containing the starting materials for thedaughter particles and the starting materials for the matrix particlesis preferably in the range of from 10⁻⁵ to 10 mol/L, more preferablyfrom 10⁻⁴ to 1 mol/L. Specifically, the concentration of the fluorinecompound is preferably not less than 10⁻⁵ mol/L, from the viewpoint ofproducing an effective amount of the fluorine compound fine particles,and the concentration is preferably not more than 10 mol/L, from theviewpoint of the solubility of the fluorine compound.

The concentration of the starting materials for the daughter particlesin the starting material liquid mixture containing the startingmaterials for the daughter particles and the starting materials for thematrix particles is preferably in the range of from 10⁻⁵ to 10 mol/L,more preferably from 10⁻⁴ to 1 mol/L. Specifically, the concentration ofthe daughter particles is preferably not less than 10⁻⁵ mol/L, from theviewpoint of providing the minimum amount necessary to achieve goodoptical properties of the daughter particles in the composite fineparticles, and the concentration is preferably not higher than 10 mol/L,from the viewpoint of sufficiently dispersing the starting materials forthe daughter particles in the liquid mixture, whereby the composite fineparticles having a uniform composition are produced.

The amount of the daughter particles dispersed in and supported by thematrix particles is not particularly limited as long as the daughterparticles can be well dispersed in the matrix particles without causingan excessive aggregation of the daughter particles in the matrixparticles. The amount of the daughter particles contained in the matrixparticles normally ranges from 0.1 to 85% by volume, preferably from 0.1to 50% by volume, more preferably from 0.1 to 30% by volume,particularly preferably from 0.5 to 20% by volume. In the case where thecomposite fine particles are coated with the inorganic materials, theamount of the inorganic material coating is subtracted when calculatingthe amount of the daughter particles. In the case where the metal oxidesand the fluorine compounds are contained in the matrix particles, theminimum amount of the fluorine compounds is not less than 1% by weight,based on the composite fine particles. The amount of the daughterparticles is calculated by the density of the materials constituting thecomposite fine particles (in the case of particles, the particledensity) and the compositional ratio of the starting material liquidmixture.

The concentration of the starting materials for the inorganic materialsin the starting material liquid mixture containing the composite fineparticles comprising the daughter particles and the matrix particles ispreferably in the range of from 10⁻⁵ to 10 mol/L, more preferably from10⁻⁴ to 1 mol/L, when the concentration of the composite fine particlesis in the range of from 10⁻⁵ to 10 mol/L. Specifically, theconcentration of the inorganic materials is preferably not less than10⁻⁵ mol/L, from the viewpoint of coating the surface of the compositefine particles to an extent sufficient for providing good coatingeffects. The concentration is preferably not higher than 10 mol/L, fromthe viewpoint of the solubility of the starting materials for theinorganic materials.

The composite fine particles, which are coated with the inorganicmaterials, and comprise the daughter particles and the matrix particlesdispersed in the liquid mixture, have an average particle diameter ofpreferably from 0.002 to 0.5 μm, specifically not greater than 0.4 μm,particularly not greater than 0.3 μm, furthermore not greater than 0.2μm, and the particle diameter distribution should preferably be kept asnarrow as possible. When the average particle diameter exceeds 0.5 μm,transparency and the ultraviolet shielding ability are likely to belowered due to the scattering of the visible light caused by the largeparticle diameter. On the other hand, when the average particle diameteris not greater than 0.5 μm, and even if the difference between therefractive index of the composite fine particles and that of thedispersion medium were large, the transparency of the composite fineparticles can be maintained at a high level without scattering of thevisible light. The average particle diameter mentioned herein ismeasured by dispersing a cake comprising the composite fine particlesafter the coating treatment in water and obtaining a particle diameterusing a particle size analyzer (for example, a laser doppler-typeparticle size analyzer "DLS-700," manufactured by OTSUKA ELECTRONICSCO., LTD.).

The ultraviolet shielding composite fine particles of the presentinvention can be obtained by the production method explained above, andthe structure of the ultraviolet shielding composite fine particles issuch that the matrix particles comprise aggregates of primary particleswhich are formed while the primary particles retain their shapes, eachprimary particle being aggregated in a close-packed state, and that thedaughter particles are dispersed on the surface and in the inner portionof the matrix particles, the composite fine particles comprising thedaughter particles and the matrix particles being preferably coated withan inorganic material having substantially no catalytic activities. Whenthe dispersibility of the daughter particles is poor, they do not showgood optical properties. When the daughter particles are present on thesurface of the matrix particles, the ultraviolet light which collideswith the daughter particles is partially absorbed while the remainingultraviolet light is scattered from the composite fine particles. Theultraviolet light which does not collide with the daughter particles onthe surface and further enters the inner portion of the matrix particlesis absorbed and scattered by the daughter particles contained in theinner portion of the matrix particles, so that the ultraviolet light iseffectively shielded. Also, because the coating layer comprises theinorganic materials, the catalytic activities of the daughter particlesand the matrix particles are substantially inhibited, so that thecomposite fine particles can be stably present in a given medium withoutcausing a deterioration of the medium.

The shapes and the sizes of the final product of the composite fineparticle powders of the present invention obtainable after the dryingand pulverization step (d) above are not particularly limited, andvarious shapes and sizes can be used according to different cases. Forinstance, when used as cosmetic powders, spherical particle powdershaving a particle diameter ranging from sub-microns to severalmicrometers are preferably used from the viewpoints of a good sense oftouch and easy handling, and the plate-like particle powders having theparticle diameter ranges given above are preferably used from theviewpoints of providing strong adherence to the skin, excellentspreading on the skin, and easy handling.

5. Optical Properties of Composite Fine Particles

The optical properties of the ultraviolet shielding composite fineparticles of the present invention can be quantitatively evaluated bymeasuring their light transmittance by an ultraviolet-visible lightspectrophotometer.

The preferred ultraviolet shielding ability for the ultravioletshielding composite fine particles of the present invention isdetermined by a light transmittance of not less than 80% at a wavelengthof 800 nm, a light transmittance of not less than 20% at a wavelength of400 nm, and a light transmittance of not more than 5% at least at onewavelength within the range from 380 nm to 300 nm. The lighttransmittance is determined by suspending the composite fine particlesin a medium having substantially the same refractive index level as thecomposite fine particles, and measuring with an ultraviolet-visiblelight spectrophotometer using an optical cell having an optical pathlength of 1 mm. By having the above optical properties, a high lighttransmittance particularly in the visible light region as well as a highshielding ability in the ultraviolet light region can be satisfactorilyachieved. Here, the phrase "a light transmittance of not more than 5% atleast at one wavelength within the range from 380 nm to 300 nm" meansthat the light transmittance is not more than 5% at least at certainwavelengths within the range of 380 nm to 300 nm, including cases wherethe light transmittance exceeds 5% in certain other ranges withinwavelengths of 380 nm to 300 nm. Incidentally, the phrase "a mediumhaving substantially the same refractive index level as the compositefine particles" means that the difference in the refractive indicesbetween a sample of the composite fine particles and the medium iswithin ±0.1, preferably within ±0.05. In this case, the concentration ofthe composite fine particles dispersed in the medium is, for instance,not less than 0.1% by weight.

The ultraviolet shielding ability mentioned above can be evaluated by anultraviolet-visible light spectroscopy specified below.

The composite fine particles of the present invention are suspended in amedium having substantially the same refractive index level as thecomposite fine particles to prepare a suspension of composite fineparticles having a given concentration. In order to prepare a uniformsuspension, the composite fine particles are stirred and well dispersedusing, for instance, an ultrasonic disperser, etc. An optical cellhaving an optical path length of 1 mm is filled with the abovesuspension. An optical cell used herein has no absorption or produces noscattering of the light in the ultraviolet light region and the visiblelight region, and, for instance, a silica cell can be used therefor. Thelight transmittance through the optical cell is measured using anultraviolet-visible light spectrophotometer. In this method, the otheroptical cell filled with a medium without suspending the composite fineparticles is used as a control to remove background.

Also, the composite fine particles of the present invention havesubstantially no catalytic activities, which may be verified by thefollowing method. Specifically, the composite fine particles aredispersed in white vaseline in an amount of 1% by weight, and theresulting mixture is subjected to a 60-minute irradiation treatment withultraviolet light having a central wavelength of 312 nm using anultraviolet light source ("ENB-260C/J," manufactured by SPECTRONICSCORPORATION), to determine whether or not discoloration of whitevaseline takes place in the resulting mixture by the irradiationtreatment mentioned above. In the case where the white vaseline isaffected by the catalytic activities, a color change undergoes of fromwhite to brown, and thus is easily verified by the above method.

Accordingly, in the present specification, the phrase "the compositefine particles having substantially no catalytic activities" refers tothe composite fine particles whose catalytic activities are inhibited tosuch an extent that for practical purposes they show substantially nocatalytic activities For instance, when the catalytic activities aretested by the above method, the color change of the vaseline is notfound.

6. Cosmetics

The cosmetics of the present invention may be prepared by optionallyblending various kinds of adjuncts conventionally used for cosmetics andthe dispersion oil agents used as a medium for dispersing theultraviolet shielding composite fine particles, in addition to the aboveultraviolet shielding composite fine particles. Examples of the cosmeticadjuncts are given below.

(1) Inorganic powders such as talc, kaolin, sericite, muscovite,phlogopite, lepidolite, biotite, synthetic golden mica, vermiculite,magnesium carbonate, calcium carbonate, diatomateous earth, magnesiumsilicate, calcium silicate, aluminum silicate, barium silicate, bariumsulfate, strontium silicate, metallic tungustates, silica,hydroxylapatite, zeolite, boron nitride, and ceramic powders.

(2) Organic powders such as nylon powders, polyethylene powders,polystyrene powders, benzoguanamine resin powders,polytetrafluoroethylene powders, distyrene-benzene polymer powders,epoxy resin powders, acrylic resin powders, and fine crystallinecellulose.

(3) Inorganic white pigments such as titanium oxide and zinc oxide;inorganic red pigments such as iron oxide (red oxide) and iron titanate;inorganic brown pigments such as γ-iron oxide; inorganic yellow pigmentssuch as yellow iron oxide and yellow ochre; inorganic black pigmentssuch as black iron oxide and carbon black; inorganic violet pigmentssuch as manganese violet and cobalt violet; inorganic green pigmentssuch as chromium oxide, chromium hydroxide, and cobalt titanate;inorganic blue pigments such as ultramarine and Prussian blue;pearl-like pigments such as mica coated with titanium oxide,oxychlorobismuth coated with titanium oxide, oxychlorobismuth, talccoated with titanium oxide, fish scale flake, mica coated with coloredtitanium oxide; and metal powder pigments such as aluminum powders andcopper powders.

(4) Organic pigments including Pigment Red 57-1, Pigment Red 57, PigmentRed 53 (Ba), Pigment Red 49 (Na), Pigment Red 63 (Ca), Vat Red 1,Pigment Red 4, Pigment Red 48, Pigment Orange 5, Pigment Orange 13,Pigment Yellow 12, Pigment Yellow 1, and Pigment Blue 15; organicpigments including zirconium lakes, barium lakes, and aluminum lakes ofAcid Red 51, Acid Red 92, Acid Red 52, Acid Red 33, Acid Red 87, AcidViolet 9, Solvent Orange 7, Acid Orange 7, Acid Yellow 23, Acid Yellow5, Acid Yellow 73, Acid Yellow 3, Food Green 3, and Food Blue 1.

(5) Natural pigments such as chlorophyll and β-carotene

(6) Various hydrocarbons, higher fatty acids, fats and oils, esters,higher alcohols, and waxes, such as squalane, paraffin wax, liquidparaffin, Vaseline™, microcrystalline wax, ozocerite, ceresine, myristicacid, palmitic acid, stearic acid, oleic acid, isostearic acid, cetylalcohol, hexadecyl alcohol, oleyl alcohol, cetyl 2-ethylhexanoate,2-ethylhexyl palmitate, 2-octyldodecyl myristate, neopentyl glycoldi-2-ethylhexanoate, glycerol tri-2-ethylhexanoate, 2-octyldodecyloleate, isopropyl myristate, glycerol triisostearate, coconut fatty acidtriglyceride, olive oil, avocado oil, camellia oil, jojoba oil, beeswax,spermaceti, carnauba wax, myristyl myristate, mink oil, and lanoline;silicone oils such as volatile silicone oils and non-volatile siliconeoils.

(7) The ultraviolet protecting agents such as ultraviolet lightabsorbents may be optionally added, if necessary. Examples of theultraviolet light absorbents include the following:

1) Benzoic acid derivatives:

p-Aminobenzoic acid (PABA), glycerol mono-p-aminobenzoate, ethylp-N,N-dipropoxyaminobenzoate, ethyl p-N,N-diethoxyaminobenzoate, ethylp-N,N-dimethylaminobenzoate, butyl p-N,N-dimethylaminobenzoate, amylp-N,N-dimethylaminobenzoate, and octyl p-N,N-dimethylaminobenzoate.

2) Anthranilic acid derivatives:

Homomenthyl N-acetylanthranilate.

3) Salicylic acid derivatives:

Amyl salicylate, menthyl salicylate, homomenthyl salicylate, octylsalicylate, phenyl salicylate, benzyl salicylate, andp-isopropanolphenyl salicylate.

4) Cinnamic acid derivatives:

Octylcinnamate, ethyl 4-isopropylcinnamate, methyl2,5-diisopropylcinnamate, ethyl 2,4-diisopropylcinnamate, methyl2,4-diisopropylcinnamate, propyl p-methoxycinnamate, isopropylp-methoxycinnamate, isoamyl p-methoxycinnamate, octyl p-methoxycinnamate(2-ethylhexyl p-methoxycinnamate), 2-ethoxyethyl p-methoxycinnamate,cyclohexyl p-methoxycinnamate, ethyl α-cyano-β-phenylcinnamate,2-ethylhexyl α-cyano-β-phenylcinnamate, and glycerolmono-2-ethylhexanoyl-diparamethoxycinnamate.

5) Benzophenone derivatives:

2,4-Dihydroxybenzophenone, 2,2'-dihydroxy 4-methoxybenzophenone,2,2'-dihydroxy 4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy 4-methoxybenzophenone, 2-hydroxy4-methoxy-4'-methylbenzophenone, 2-hydroxy4-methoxybenzophenone-5-sulfonate, 4-phenylbenzophenone, 2-ethylhexyl4'-phenylbenzophenone-2-carboxylate, 2-hydroxy 4-n-octoxybenzophenone,and 4-hydroxy 3-carboxybenzophenone.

6) Other ultraviolet absorbents:

3-(4'-Methylbenzylidene) d,l-camphor, 3-benzylidene d,l-camphor,urocanic acid, ethyl urocanate, 2-phenyl 5-methylbenzoxazole,2,2'-hydroxy 5-methylphenylbenzotriazole, 2-(2'-hydroxy-5't-octylphenyl)benzotriazole, dibenzarsine, dianisoylmethane, 4-methoxy4'-t-butyldibenzoylmethane,5-(3,3'-dimethyl-2-norbornylidene)-3-pentane-2-one, and1-(3,4-dimethoxyphenyl)-4,4'-dimethyl-1,3-pentadione.

(8) Also, surfactants may be optionally used.

Examples of the surfactants include polyoxyethylene alkyl ethers,polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acidesters, polyoxyethylene sorbitol fatty acid esters, alkylpolyoxyethylene hardened castor oil sulfates, alkyl polyoxyethylenesulfates, alkyl phosphates, alkyl polyoxyethylene phosphates, alkalimetal salts of fatty acids, sorbitan fatty acid esters, glycerol fattyacid esters, and silicone-based surfactants, such as polyether-modifiedsilicones.

(9) Further, water-soluble polyhydric alcohols may be optionally used.Examples of the water-soluble polyhydric alcohols are water-solublepolyhydric alcohols having two or more hydroxyl groups in a molecule,including ethylene glycol, propylene glycol, 1,3-butylene glycol,1,4-butylene glycol, dipropylene glycol, glycerol, polyglycerols, suchas diglycerol, triglycerol, and tetraglycerol, glucose, maltose,maltitol, sucrose, fructose, xylitol, sorbitol, maltotriose, threitol,erythritol, and sugar alcohol derived from decomposed starch.

(10) In addition, other cosmetic adjuncts may be optionally added,including amino acids, such as lysine and arginine; organic acids, suchas lactic acid, citric acid, succinic acid, and glycolic acid, andorganic salts thereof; resins, such as alkyd resins and urea resins;plasticizers, such as camphor and tributyl citrate; antioxidants, suchas α-tocopherol; antiseptics, such as butyl p-hydroxybenzoate and methylp-hydroxybenzoate; extracts from plants, such as cornflower, althea, andHypericuor erectum; bioactive substances such as retinol and allantoin;binders such as xanthan gum and carrageenan; and perfumes.

In order to improve the sense of touch and enjoy the continuality of theultraviolet shielding effects, one or more silicone oils andether-modified silicones may be incorporated in the cosmetics of thepresent invention.

The silicones are not particularly limited as long as they are thosenormally incorporated in cosmetics. Examples thereof include octamethylpolysiloxane, tetradecamethyl polysiloxane, methyl polysiloxane,high-molecular methyl polysiloxane, methylphenyl polysiloxane,octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane,trimethylsiloxysilicate, and organopolysiloxanes having a repeating unitrepresented by the general formula (1) or the general formula (2) givenbelow: ##STR1## wherein R¹ and R², which may be identical or different,independently stand for an alkyl group having 1 to 4 carbon atoms; R³stands for a linear, branched, or cyclic alkyl group, a linear,branched, or cyclic alkenyl group, or a linear, branched, or cyclicfluoroalkyl group, each having 1 to 40 carbon atoms; "e" stands for anumber of not less than 2, and "f" stands for a number of not less than3, wherein the sum of "e" and "f" is a number 5 to 6,000.

The amount of the silicone oils given above is from 2 to 80% by weight,preferably from 5 to 50% by weight, more preferably from 8 to 40% byweight in the cosmetic composition.

The ether-modified silicones are not particularly limited as long asthey are compounds in which at least a part of the siloxane issubstituted by one or more groups having an ether bond. Examples thereofare given below, which may be used singly or in a combination of two ormore kinds.

Specific examples of the ether-modified silicones include the followingcompounds (1) to (4):

1! The ether-modified silicones having the following genera formula (3):##STR2## wherein at least one of R¹¹, R¹², and R¹³ stands for a grouphaving the general formula R¹⁴ (OC₃ H₆)_(b) (OC₂ H₄)_(a) O(CH₂)_(p) --,wherein R¹⁴ stands for a hydrogen atom or an alkyl group having 1 to 12carbon atoms; "a" and "b" independently stand for a number of from 0 to35, "a" and "b" being average values; and p stands for a number of from1 to 5, and the remaining R¹¹, R¹², and R¹³ excluding those definedabove each stands for a methyl group; "m" stands for a number of from 1to 200, and "n" stands for a number of from 0 to 50, "m" and "n" beingaverage values.

Among the ether-modified silicones defined in 1! above, a preference isgiven to those having a molecular weight of from 2,000 to 50,000 wherethe amount occupied by substituents R¹¹ to R¹³ is from 5 to 40% Further,in the general formula (3), a preference given to the ether-modifiedsilicones defined in 1! above wherein "m" is from 5 to 80, "n" is from 0to 2, "a" is from 9 to 10, "b" is equal to 0, "p" is equal to 3, and R¹⁴stands for a hydrogen atom, or the ether-modified silicones defined in1! above wherein "m" is from 90 to 110, "n" is equal to 0, "a" is from11 to 13, "b" is equal to 0, "p" is equal to 3, and R¹⁴ stands for ahydrogen atom.

Specific examples of the ether-modified silicones having the generalformula (3) above include a commercially available product "SH-3775Series" manufactured by Toray-Dow Corning Corporation.

2! The polyether-alkyl-modified silicones having the following generalformula (4): ##STR3## wherein R²¹ stands for a hydrocarbon group having1 to 5 carbon atoms, R²² stands for a hydrocarbon group having 6 to 16carbon atoms, Q stands for an alkylene group, R²³ stands for a grouphaving the general formula --(OC₂ H₄)_(q) --(OC₃ H₆)_(r) --OR²⁴, whereinR²⁴ stands for a hydrogen atom or a lower alkyl group, "q" and "r" eachstands for a number satisfying the relationship of q≦r, wherein themolecular weight of a --(OC₂ H₄)_(q) --(OC₃ H₆)_(r) -- moiety is from600 to 3,500; z stands for a number of from 1 to 3; x and y each standsfor a number satisfying the relationships of x<3y and x+y+z=30 to 400,with proviso that the entire weight of the --(OC₂ H₄)_(q) --(OC₃ H₆)_(r)--moiety does not exceed one-third of the entire weight of thepolyether-alkyl-modified silicone.

The hydrocarbon groups having 1 to 5 carbon atoms represented by R²¹ inthe general formula (4) include alkyl groups and alkenyl groups having 1to 5 carbon atoms. Examples thereof include a methyl group, an ethylgroup, a propyl group, an isopropyl group, a butyl group, a pentylgroup, or a vinyl group, among which a preference is given to a methylgroup. In addition, examples of the hydrocarbon groups having 6 to 16carbon atoms represented by R²² include linear alkyl groups, such as ahexyl group, a heptyl group, an octyl group, a nonyl group, a decylgroup, an undecyl group, a dodecyl group, a tetradodecyl group, ahexadecyl group; branched alkyl groups, such as an isooctyl group, ans-octyl group, and a 2-ethylhexyl group, among which a preference isgiven to a dodecyl group. Incidentally, in the case where y is greaterthan 1, R²² may be identical or different for each of the repeatingunits.

Examples of the alkylene groups represented by Q in the general formula(4) include a methylene group, an ethylene group, a propylene group, atrimethylene group, and a tetramethylene group, among which a preferenceis given to a propylene group and a trimethylene group.

In the general formula (4), R²⁴, which is a group included in a grouprepresented by R²³, stands for a hydrogen atom or a lower alkyl group,such as a methyl group, an ethyl group, a propyl group, an isopropylgroup, or a butyl group, among which a preference is given to a hydrogenatom. In addition, preferred values of "q" and "r" are q=15 and r=0; orq=r=25; or q=29 and r=7.

Specific examples of the polyether-alkyl-modified silicones having thegeneral formula (4) include "DC Q2-2500," manufactured by Toray-DowCorning Corporation (laurylmethycone copolyol, wherein R²¹ stands for amethyl group, R²² stands for a dodecyl group, and x is equal to 0 in thegeneral formula (4).

3! The alkylglycerylether-modified silicones having the followinggeneral formula (5): ##STR4## wherein at least one of R³¹, R³², R³³, andR³⁴ stands for a group having the general formula (6) --A--OCH₂CH(OR⁴¹)CH₂ OR⁴², wherein A stands for a divalent hydrocarbon grouphaving 3 to 20 carbon atoms; and R⁴¹ and R⁴² each independently standsfor a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms,with proviso that at least one of R⁴¹ and R⁴² is a hydrogen atom; theremaining R³¹, R³², R³³, and R³⁴ excluding those defined above eachstands for a linear, branched, or cyclic hydrocarbon group having 1 to30 carbon atoms, or a group having the general formula -BR⁴³, wherein Bstands for a divalent hydrocarbon group having an ether bond and/or anester bond; R⁴³ stands for a linear, branched, or cyclic hydrocarbongroup having 1 to 30 carbon atoms; "s", "t", and "u" each independentlystands for a number of from 0 to 200, and when s+t+u=0, one or more R³¹groups stand for a group having the general formula (6) defined above,excluding the case where at least one of R³¹ having the general formula(6) is such that A stands for a trimethylene group, each of R⁴¹ and R⁴²stands for a hydrogen atom; and each of the remaining substituents R³¹,R³², R³³, and R³⁴ which is not defined above stands for a methyl group.

Examples of the divalent hydrocarbon groups having 3 to 20 carbon atomsrepresented by A in the general formula (5) above include linearalkylene groups, such as a trimethylene group, a tetramethylene group, apentamethylene group, a hexamethylene group, a heptamethylene group, anoctamethylene group, a nonamethylene group, a decamethylene group, anundecamethylene group, a dodecamethylene group, a tetradecamethylenegroup, a hexadecamethylene group, and an octadecamethylene group; andbranched alkylene groups, such as a propylene group, a2-methyltrimethylene group, a 2-methyltetramethylene group, a2-methylpentamethylene group, and a 3-pentamethylene group. Examples ofthe hydrocarbon groups having 1 to 5 carbon atoms represented by R⁴¹ andR⁴² include linear, branched, or cyclic alkyl groups, such as a methylgroup, an ethyl group, a propyl group, an isopropyl group, a butylgroup, a pentyl group, an s-butyl group, a t-butyl group, a neopentylgroup, and a cyclopentyl group. Further, examples of the divalenthydrocarbon groups having an ether bond and/or an ester bond representedby B include groups having the following general formulas: --(CH₂)_(h)--(OC₂ H₄)_(i) --(OC₃ H₆)_(j) --O--, --(CH₂)_(h) --O--CO--, and--(CH₂)_(h) --COO--, wherein "h" stands for an integer of from 3 to 20,and "i" and "j" independently represents a number of from 0 to 50.

In addition, examples of the linear, branched, or cyclic hydrocarbongroups having 1 to 30 carbon atoms represented by R⁴³ include linearalkyl groups, such as a methyl group, an ethyl group, a propyl group, abutyl group, a pentyl group , a hexyl group, a heptyl group, an octylgroup, a nonyl group, a decyl group, an undecyl group, a dodecyl group,a tetradecyl group, a hexadecyl group, an octadecyl group, an eicosylgroup, a doeicosyl, a tetraeicosyl group, a hexaeicosyl group, anoctaeicosyl group, and a triacontyl group; branched alkyl groups, suchas an isopropyl group, an s-butyl group, a t-butyl group, a neopentylgroup, a 1-ethylpropyl group, and a 1-heptyldecyl group; and cyclicalkyl groups, such as a cyclopentyl group, a cyclohexyl group, anabietyl group, and a cholesteryl group.

The alkylglyceryl ether-modified silicones represented by the generalformula (5) can be produced by the method disclosed in Japanese PatentLaid-Open No. 4-108795.

The amount of the ether-modified silicones given above is preferablyfrom 0.05 to 20% by weight, particularly 1 to 10% by weight in thecosmetic composition.

Although an amount of the ultraviolet shielding composite fine particlesof the present invention in cosmetics depends upon the kinds ofcosmetics produced, the amount is preferably 0.01 to 50% by weight, morepreferably 0.05 to 40% by weight, particularly 0.1 to 30% by weight.When the amount of the ultraviolet shielding composite fine particles isless than 0.01% by weight, sufficient shielding effects against theultraviolet light cannot be achieved, and when the amount exceeds 50% byweight, a pleasant sense of touch when used as cosmetics are undesirablylost. The amount of the ultraviolet shielding composite fine particleswhen using a dispersion oil agent composition thereof for cosmetics isdetermined so as to satisfy the amount specified in the cosmeticscontained in the dispersion oil agent, the cosmetics comprising theultraviolet shielding composite fine particles mentioned above.

The cosmetics of the present invention may be formulated in variousforms as conventionally prepared. Although the forms are notparticularly limited, the cosmetics may be formulated as various make-upproducts including lotions, emulsions, creams, ointments, aerosolcosmetics, powdery foundations, powdery eyeshadows, emulsifiedfoundation creams, lipsticks, hair care preparations, and skin cleaners.

In addition, the cosmetics of the present invention preferably have SPFof not less than 8 and changes in color before and after skinapplication, determined as AE measured by color-and-color differencemeter of not more than 3. From the viewpoint of sufficiently exhibitingthe ultraviolet shielding effects, SPF is preferably not less than 8,more preferably not less than 10, particularly not less than 13. Fromthe viewpoint of maintaining good appearance upon skin application,ΔE*_(ab) is preferably not more than 3, more preferably not more than 2,particularly not more than 1. In the present invention, SPF is measuredby using an analyzer "SPF-290" (manufactured by The Optometrics Group),and ΔE*_(ab) is a value defined in JIS Z8729-1980.

The present invention will be explained hereinafter in more detail bymeans of the following examples, without intending to limit the scope ofthe present invention thereto.

EXAMPLE 1

366.5 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight) and 20.0 g oftitanium oxide ultrafine particles ("TTO-51(A)," manufactured byIshihara Sangyo Kaisha, Ltd.; rutile-type) were mixed. To the mixture,water was added to make up a volume of one liter, yielding a startingmaterial liquid mixture Specifically, the concentrations of SiO₂ andTiO₂ in the starting material liquid mixture were 1.25 mol/liter and0.25 mol/liter, respectively, and the amount of the daughter-and-matrixparticle mixture contained in the above starting material liquid mixturewas about 10% by weight.

Next, glass beads (average particle diameter: 0.1 mm) were added to theabove starting material liquid mixture, to give a weight ratio of thestarting material liquid mixture to the glass beads of 175:325. Theresulting mixture was subjected to a dispersion treatment for 6 hoursusing a beads mill ("TSG-6H," manufactured by Igarashi Kikai) at anagitation speed of 2000 r.p.m. After termination of the dispersiontreatment, the glass beads were removed to give a liquid dispersioncontaining the composite fine particles of TiO₂ /SiO₂ (the expressionindicated herein is used in terms of daughter particles/matrixparticles, the same could be said for the other examples set forthbelow).

84.6 g of the above liquid dispersion, 1500 g of ethanol, and 16.26 g oftetraethoxysilane were mixed, and the contents were heated to 50° C. ina water bath. After the temperature of the resulting mixture reached 50°C., a mixed solution of 3.9 ml of 1 N-hydrochloric acid and 300 g ofethanol was added dropwise to the liquid dispersion. After the dropwiseaddition was completed, the contents were allowed to react with oneanother at 50° C. for 2 hours and 30 minutes, to thereby surface-coatthe composite fine particles with SiO₂. After the coating treatment wascompleted, a mixed solution of 0.98 ml of 4 N-sodium hydroxide aqueoussolution and 50 g of ethanol was added to the resulting mixture toneutralize the hydrochloric acid. All of the above steps were carriedout under stirring.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation using a centrifuge, to give anethanol-containing cake. The procedure of adding ethanol to theresulting cake to disperse the cake in ethanol and then subjecting theresulting dispersion to a solid-liquid separation using a centrifuge wasrepeated five times, to give an ethanol-containing cake of the compositefine particles having a solid component concentration of about 40% byweight.

Thereafter, 12.5 g of the ethanol-containing cake obtained above wasmixed with 500 g of acetone, and the resulting mixture was subjected toan ultrasonic dispersion treatment. After the cake was completelydispersed in acetone, a water-repellent treatment was carried out byadding and mixing 2.0 g of methyl hydrogen polysiloxane ("KF99P,"manufactured by Shin-Etsu Silicone Corporation) with the liquiddispersion obtained above. Thereafter, a drying treatment for thecomposite fine particles was carried out by drying the resulting liquiddispersion at 80° C., and then baking the resulting mixture at 130° C.for 2 hours. The resulting powder was repeatedly pulverized ten timesusing a mill ("A10," manufactured by IKA-Labourtechnik), to give thecomposite fine particles.

The particle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, the composite fine particles werewhite. The particles were observed by a scanning electron microscope(JSM-T100, manufactured by JEOL Ltd.). As a result, it was found thatthe particles had an average particle diameter of about 1 μm. Also, across section of the particles was observed by a transmission electronmicroscope (JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathinsectioning method. Consequently, it was found that TiO₂ ultrafineparticles (average particle diameter: about 0.01 μm) were dispersed inand supported by aggregates of SiO₂ ultrafine particles (averageparticle diameter: about 0.01 μm). In other words, the composite fineparticles were TiO₂ /SiO₂ composite fine particles; matrix particleswere the aggregates of SiO₂ particles having a band gap energy of about6.2 eV and a refractive index of about 1.46; and daughter particles wereTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71 (rutile-type).

The amount of the daughter particles in the above composite fineparticles was about 8.5% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.57, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 13.6% by volume.

The composite fine particles before and after the water-repellenttreatment were dispersed in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of thedaughter particles of 1% by weight in a mixture comprising whitevaseline and the composite fine particles. The resulting mixture wassubjected to a 60-minute irradiation treatment with ultraviolet lighthaving a central wavelength of 312 nm using an ultraviolet light source("ENB-260C/J," manufactured by SPECTRONICS CORPORATION). As a result,for both liquid dispersions containing the composite fine particlesbefore and after the water-repellent treatment, no color change of thewhite vaseline was observed The above showed that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After the water-repellent treatment, when the composite fine particleswere mixed with water, they showed a strong water repellent propertyWhen the composite fine particles were mixed with a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40), the composite fine particles were rapidly dispersed in thesilicone oil. 8.4 mg of the composite fine particles having the aboverefractive index were dispersed in 2 g of the silicone oil. The lighttransmittance of the resulting liquid dispersion was evaluated by anultraviolet-visible light spectrophotometer ("UV-160A," manufactured byShimadzu Corporation). The light transmittance was measured using asilicious cell having an optical path length of 1 mm in a wavelength offrom 200 to 800 nm. The results are shown in FIG. 1.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles showed remarkablyhigh light transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 52%, and at 800 nm being 81%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 2

366.5 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight) and 20.3 g ofzinc oxide ultrafine particles ("FINEX 75," manufactured by SakaiChemical Industry Co., Ltd.) were mixed. To the mixture, water was addedto make up a volume of one liter, yielding a starting material liquidmixture. Specifically, the concentrations of SiO₂ and ZnO in thestarting material liquid mixture were 1.25 mol/liter and 0.25 mol/liter,respectively, and the amount of the daughter-and-matrix particle mixturecontained in the above starting material liquid mixture was about 10% byweight.

Thereafter, the procedure of dispersing the starting material liquidmixture thus prepared using a high-pressure dispersing device ("LA-31,"manufactured by Nanomizer INC.) was repeated ten times under thedisintegration pressure of 1000 kg/cm². By the above dispersiontreatment, a liquid dispersion containing ZnO/SiO₂ composite fineparticles was obtained.

1500 g of ethanol, 16.26 g of tetraethoxysilane, and 3.9 ml of 1N-hydrochloric acid were mixed, and the contents were heated to 50° C.in a water bath. After the temperature of the resulting mixture reached50° C., the reaction mixture was matured for 2 hours and 30 minutes.After the maturation was completed, a mixed solution of 0.98 ml of 4N-sodium hydroxide aqueous solution and 50 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. Thereafter, amixed solution of 84.6 g of the above liquid dispersion and 300 g ofethanol was added dropwise to the neutralized solution. After thedropwise addition was completed, the contents were allowed to react withone another at 50° C., to thereby surface-coat the composite fineparticles with SiO₂. All of the above steps were carried out understirring.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol-containing cake of the composite fine particles having a solidcomponent concentration of about 40% by weight

Thereafter, 12.5 g of the ethanol-containing cake obtained above wasmixed with 500 g of acetone, and the resulting mixture was subjected toan ultrasonic dispersion treatment. After the cake was completelydispersed in acetone, a water-repellent treatment was carried out byadding and mixing 0.5 g of methyl hydrogen polysiloxane ("KF99P,"manufactured by Shin-Etsu Silicone Corporation) with the liquiddispersion obtained above. Thereafter, a drying treatment for thecomposite fine particles was carried out by drying the resulting liquiddispersion at 80° C., and then baking the resulting mixture at 130° C.for 2 hours. The resulting powder was repeatedly pulverized ten timesusing a mill ("A10," manufactured by IKA-Labourtechnik), to give thecomposite fine particles.

The particle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter in the same manner as in Example 1. Itwas found that the average particle diameter, based on volume, was about0.07 μm.

After the water-repellent treatment, the composite fine particles werewhite. The particles were observed by a scanning electron microscope(JSM-T100, manufactured by JEOL Ltd.). As a result, it was found thatthe particles had an average particle diameter of about 1 μm. Also, across section of the particles was observed by a transmission electronmicroscope (JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathinsectioning method. Consequently, it was found that ZnO ultrafineparticles (average particle diameter: about 0.01 μm) were dispersed inand supported by aggregates of SiO₂ ultrafine particles (averageparticle diameter: about 0.01 μm). In other words, the composite fineparticles were ZnO/SiO₂ composite fine particles; matrix particles werethe aggregates of SiO₂ particles having a band gap energy of about 6.2eV and a refractive index of about 1.46; and daughter particles were ZnOparticles having a band gap energy of about 3.2 eV and a refractiveindex of about 1.99.

The amount of the daughter particles in the above composite fineparticles was about 5.9% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andZnO were 2.27 g/cm³ and 5.78 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.49, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 9.6% by volume.

The composite fine particles before and after the water-repellenttreatment were dispersed in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the ZnOparticles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After the water-repellent treatment, when the composite fine particleswere mixed with water, they showed a strong water repellent property.When the composite fine particles were mixed with a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40), the composite fine particles were rapidly dispersed in thesilicone oil. 28 mg of the composite fine particles having the aboverefractive index were dispersed in 2 g of the silicone oil. The lighttransmittance of the resulting liquid dispersion was evaluated in thesame manner as in Example 1. The results are shown in FIG. 2.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region A, theultraviolet region B, and the ultraviolet region C, the wavelengths ofwhich were not longer than 350 nm. On the other hand, the composite fineparticles show remarkably high light transmittance values in the entirevisible light region at a wavelength of from 400 to 800 nm, the lighttransmittance at 400 nm being 30%, and at 800 nm being 84%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 3

The formation of the TiO₂ /SiO₂ composite fine particles, the SiO₂surface coating treatment, and the solid-liquid separation were carriedout in the same manner as in Example 1, to give an ethanol-containingcake of the composite fine particles having a solid componentconcentration of about 40% by weight.

Thereafter, 12.5 g of the ethanol-containing cake obtained above wasmixed with 500 g of ethyl acetate, and the resulting mixture wassubjected to an ultrasonic dispersion treatment. After the cake wascompletely dispersed in ethyl acetate, a water-repellent treatment wascarried out by adding 2.5 g of an amino-modified silicone ("X-22-9261,"manufactured by Shin-Etsu Silicone Corporation; molecular weight: 30000;and amino equivalency: 4980) to the liquid dispersion obtained above,and subjecting the resulting mixture to a further ultrasonic treatmentat 50° C. for 3 hours.

42.5 g of a silicone oil ("KF96A," manufactured by Shin-Etsu SiliconeCorporation; refractive index: 1.40) was added to the above liquiddispersion, followed by stirring and mixing. Thereafter, the resultingmixture was subjected to a topping treatment at 80° C. using a rotaryevaporator to remove ethyl acetate, so that the composite fine particleswere phase-transferred and dispersed in the silicone oil, to give asilicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

The particle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andmeasuring the particle diameter in the same manner as in Example 1. Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles were TiO₂particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 8.5% by volume, which was calculated based on thecompositional ratio of the particles in the starting material liquidmixture and the amount of SiO₂ coating, wherein particle densities ofSiO₂ and TiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. Therefractive index of the composite fine particles was about 1.57, therefractive index being calculated from the amount of the daughterparticles in the composite fine particles. Incidentally, the amount ofthe daughter particles dispersed in and supported by aggregates of thematrix particles, which did not include the SiO₂ coating layer portion,was about 13.6% by volume.

The silicone oil dispersion of the composite fine particles thusobtained was diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles thus obtained was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 3.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 80%, and at 800 nm being 97%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 4

366.5 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight), 10.0 g oftitanium oxide ultrafine particles ("TTO-51(A)," manufactured byIshihara Sangyo Kaisha, Ltd.; rutile-type), and 40.7 g of zinc oxideultrafine particles ("FINEX 75," manufactured by Sakai Chemical IndustryCo., Ltd.) were mixed. To the mixture, water was added to make up avolume of one liter, yielding a starting material liquid mixture.Specifically, the concentrations of SiO₂, TiO₂, and ZnO in the startingmaterial liquid mixture were 1.25 mol/liter, 0.125 mol/liter, and 0.5mol/liter, respectively, and the amount of the daughter-and-matrixparticle mixture contained in the above starting material liquid mixturewas about 12% by weight.

The resulting starting material liquid mixture was subjected to adispersion treatment in the same manner as in Example 1, to give aliquid dispersion containing the composite fine particles of TiO₂+ZnO/SiO₂. Thereafter, the resulting liquid dispersion was subjected toa SiO₂ surface-coating treatment, which was carried out in the samemanner as in Example 2. Subsequent to the coating treatment, after theliquid dispersion was heated to 70° C., a water-repellent treatment wascarried out by adding 0.74 g of an amino-modified silicone("XF42-B0819," manufactured by Toshiba Silicone Corporation; molecularweight: 10000; and amino equivalency: 1600) to the liquid dispersionobtained above, and subjecting the resulting mixture to a furtherultrasonic treatment for the composite fine particles of TiO₂ +ZnO/SiO₂at 70° C. for 2 hours.

After the water-repellent treatment, the liquid dispersion was subjectedto a topping treatment at 75° C. using a rotary evaporator to removeethanol and water, to thereby produce a liquid dispersion which wasconcentrated three times that of the liquid dispersion before thetopping treatment. Thereafter, 900 g of n-hexane was added, and theresulting mixture was subjected to a reflux and dehydration treatment at70° C.

After the reflux and dehydration treatment, 132.8 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the above liquid dispersion, followed bystirring and mixing. Thereafter, the resulting mixture was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol and water, so that the composite fine particles werephase-transferred and dispersed in the silicone oil, to give a siliconeoil dispersion of the composite fine particles having a concentration ofthe composite fine particles of 10% by weight.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.09 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) and ZnO ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ +ZnO/SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71 and ZnO particles having a band gap energy of about3.2 eV and a refractive index of about 1.99.

The amount of the daughter particles in the above composite fineparticles was about 14.1% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂,TiO₂, and ZnO were 2.27 g/cm³, 3.84 g/cm³, and 5.78 g/cm³, respectively.The refractive index of the composite fine particles was about 1.56, therefractive index being calculated from the amount of the daughterparticles in the composite fine particles. Incidentally, the amount ofthe daughter particles dispersed in and supported by aggregates of thematrix particles, which did not include the SiO₂ coating layer portion,was about 22.6% by volume

The composite fine particles before the water-repellent treatment werediluted in white vaseline (manufactured by Wako Pure ChemicalIndustries, Ltd.), so as to have a concentration of the TiO₂ particlesof 1% by weight in a mixture comprising white vaseline and the compositefine particles. Thereafter, the determination of color change wascarried out in the same manner as in Example 1. The above showed that nocolor change took place in the white vaseline, and that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles thus obtained was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 4.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region A, theultraviolet region B, and the ultraviolet region C, the wavelengths ofwhich were not longer than 350 nm. On the other hand, the composite fineparticles show extremely high light transmittance values in the entirevisible light region at a wavelength of from 400 to 800 nm, the lighttransmittance at 400 nm being 40%, and at 800 nm being 94%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 5

The preparation of the starting material liquid mixture and thedispersion treatment were carried out in the same manner as in Example1, to give a liquid dispersion containing the composite fine particlesof TiO₂ /SiO₂.

84.6 g of the above liquid dispersion, 1500 g of ethanol, and 16.26 g oftetraethoxysilane were mixed, and the contents were heated to 50° C. ina water bath. After the temperature of the resulting mixture reached 50°C., a mixed solution of 3.9 ml of 1 N-hydrochloric acid and 300 g ofethanol was added dropwise to the liquid dispersion. After the dropwiseaddition was completed, the contents were allowed to react with oneanother at 50° C. for 2 hours and 30 minutes, to thereby surface-coatthe composite fine particles with SiO₂. After the formation of the SiO₂surface-coating was completed, 199.1 g of an isopropyl alcohol solutioncontaining 0.04% by weight of aluminum isopropoxide was added dropwiseto the resulting mixture, and the mixture was allowed to react with oneanother at 75° C. for 5 hours, to thereby further form an A1₂ O₃ surfacecoating. After the coating treatment was completed, a mixed solution of0.98 ml of 4 N-sodium hydroxide aqueous solution and 50 g of ethanol wasadded to the resulting mixture to neutralize the hydrochloric acid. Allof the above steps were carried out under stirring.

After the coating treatment, 6.6 g of oleic acid was added to the liquiddispersion, and the resulting mixture was stirred. Thereafter, awater-repellent treatment was carried out for the TiO₂ /SiO₂ compositefine particles by subjecting the resulting mixture to an ultrasonictreatment at 50° C. for 3 hours.

After the water-repellent treatment, the liquid dispersion was subjectedto a topping treatment at 75° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, to thereby produce a liquiddispersion which was concentrated three times that of the liquiddispersion before the topping treatment. Thereafter, 900 g of n-hexanewas added, and the resulting mixture was subjected to a reflux anddehydration treatment at 70° C.

After the reflux and dehydration treatment, 111.7 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the above liquid dispersion, followed bystirring and mixing. Thereafter, the resulting mixture was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles were TiO₂particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71 (rutile-type).

The amount of the daughter particles in the above composite fineparticles was about 8.5% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.57, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 13.6% by volume.

The composite fine particles before and after the water-repellenttreatment were dispersed in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of thedaughter particles of 1% by weight in a mixture comprising whitevaseline and the composite fine particles. Thereafter, the determinationof color change was carried out in the same manner as in Example 1. Theabove showed that no color change took place in the white vaseline, andthat the catalytic activities were substantially inhibited in theresulting composite fine particles.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.09 μm.

After 0.15 g of the silicone oil dispersion of the composite fineparticles thus obtained was diluted with 4.85 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 5.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 59%, and the light transmittance at 800 nm being 87%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 6

The preparation of the starting material liquid mixture and thedispersion treatment were carried out in the same manner as in Example4, to give a liquid dispersion containing the composite fine particlesof TiO₂ +ZnO/SiO₂.

1500 g of ethanol, 16.26 g of tetraethoxysilane, and 3.9 ml of 1N-hydrochloric acid were mixed, and the contents were heated to 50° C.in a water bath. After the temperature of the resulting mixture reached50° C., the reaction mixture was matured for 2 hours and 30 minutes.After the maturation was completed, a mixed solution of 0.98 ml of 4N-sodium hydroxide aqueous solution and 50 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. Thereafter, amixed solution of 84.6 g of the above liquid dispersion containing theTiO₂ +ZnO/SiO₂ composite fine particles and 300 g of ethanol was addeddropwise to the neutralized solution. After the dropwise addition wascompleted, the contents were allowed to react with one another at 50° C.for 2 hours and 30 minutes, to thereby surface-coat the TiO₂ +ZnO/SiO₂composite fine particles with SiO₂. After the formation of the SiO₂surface-coating was completed, 199.1 g of an isopropyl alcohol solutioncontaining 0.04% by weight of aluminum isopropoxide was added dropwiseto the resulting mixture, and the mixture was allowed to react with oneanother at 75° C. for 5 hours, to thereby further form an Al₂ O₃ surfacecoating. All of the above steps were carried out under stirring.

After the coating treatment, 1.5 g of stearic acid was added to theliquid dispersion, and the resulting mixture was stirred. Thereafter, awater-repellent treatment was carried out for the TiO₂ +ZnO/SiO₂composite fine particles by subjecting the liquid dispersion obtained toan ultrasonic treatment at 70° C. for 2 hours.

The liquid dispersion obtained by the water-repellent treatment wassubjected to a reflux and dehydration treatment in the same manner as inExample 5. After the reflux and dehydration treatment, 132.0 g of asilicone oil ("KF96A," manufactured by Shin-Etsu Silicone Corporation;refractive index: 1.40) was added to the above liquid dispersion,followed by stirring and mixing. Thereafter, the resulting mixture wassubjected to a topping treatment at 80° C. using a rotary evaporator toremove ethanol, isopropyl alcohol, and water, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that ZnO ultrafine particles (averageparticle diameter: about 0.01 μm) and TiO₂ ultrafine particles (averageparticle diameter: about 0.01 μm) were dispersed in and supported byaggregates of SiO₂ ultrafine particles (average particle diameter: about0.01 μm). In other words, the composite fine particles were TiO₂+ZnO/SiO₂ composite fine particles; matrix particles were the aggregatesof SiO₂ particles having a band gap energy of about 6.2 eV and arefractive index of about 1.46; and daughter particles comprise ZnOparticles having a band gap energy of about 3.2 eV and a refractiveindex of about 1.99 and TiO₂ particles having a band gap energy of about3.3 eV and a refractive index of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 14.1% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂,TiO₂, and ZnO were 2.27 g/cm³, 3.84 g/cm³, and 5.78 g/cm³, respectively.The refractive index of the composite fine particles was about 1.56, therefractive index being calculated from the amount of the daughterparticles in the composite fine particles. Incidentally, the amount ofthe daughter particles dispersed in and supported by aggregates of thematrix particles, which did not include the SiO₂ coating layer portion,was about 22.6% by volume.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700" manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.10 μm.

The composite fine particles before the water-repellent treatmentobtainable from the ethanol-containing cake of the composite fineparticles were diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 6.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region A, theultraviolet region B, and the ultraviolet region C, the wavelengths ofwhich were not longer than 350 nm. On the other hand, the composite fineparticles show high light transmittance values in the entire visiblelight region at a wavelength of from 400 to 800 nm, the lighttransmittance at 400 nm being 33%, and at 800 nm being 93%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 7

The formation of the TiO₂ /SiO₂ composite fine particles was carried outin the same manner as in Example 1. Subsequently, the SiO₂surface-coating treatment and the Al₂ O₃ surface-coating treatment werecarried out in the same manner as in Example 5.

After the surface-coating treatment, a water-repellent treatment wascarried out by adding 0.66 g of dialkylphosphate ("DAP60H," manufacturedby Kao Corporation) to the liquid dispersion, and subjecting theresulting mixture containing the TiO₂ /SiO₂ composite fine particles toa further ultrasonic treatment at 75° C. for 1 hour.

After the water-repellent treatment, the liquid dispersion was subjectedto a topping treatment at 75° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, to thereby produce a liquiddispersion which was concentrated three times that of the liquiddispersion before the topping treatment. Thereafter, 900 g ofcyclohexane was added, and the resulting mixture was subjected to areflux and dehydration treatment at 70° C.

After the reflux and dehydration treatment, 117.7 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the above liquid dispersion, followed bystirring and mixing. Thereafter, the resulting mixture was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 8.5% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.57, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 13.6% by volume.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.09 μm.

The composite fine particles before the water-repellent treatmentobtainable from the ethanol-containing cake of the composite fineparticles were diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 7.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 74%, and at 800 nm being 96% Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 8

The formation of the TiO₂ +ZnO/SiO₂ composite fine particles, the SiO₂surface-coating treatment, and the Al₂ O₃ surface-coating treatment werecarried out in the same manner as in Example 6.

After the surface-coating treatments, a water-repellent treatment wascarried out by adding 0.74 g of dialkylphosphate ("DAP60H," manufacturedby Kao Corporation) to the liquid dispersion, and subjecting theresulting mixture containing the TiO₂ +ZnO/SiO₂ composite fine particlesto a further ultrasonic treatment at 75° C. for 1 hour.

After the water-repellent treatment, the liquid dispersion was subjectedto a reflux and dehydration treatment in the same manner as in Example5. After the reflux and dehydration treatment, 132.8 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the above liquid dispersion, followed bystirring and mixing. Thereafter, the resulting mixture was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that ZnO ultrafine particles (averageparticle diameter: about 0.01 μm) and TiO₂ ultrafine particles (averageparticle diameter: about 0.01 μm) were dispersed in and supported byaggregates of SiO₂ ultrafine particles (average particle diameter: about0.01 μm). In other words, the composite fine particles were TiO₂+ZnO/SiO₂ composite fine particles; matrix particles were the aggregatesof SiO₂ particles having a band gap energy of about 6.2 eV and arefractive index of about 1.46; and daughter particles comprise ZnOparticles having a band gap energy of about 3.2 eV and a refractiveindex of about 1.99 and TiO₂ particles having a band gap energy of about3.3 eV and a refractive index of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 14.1% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂,TiO₂, and ZnO were 2.27 g/cm³, 3.84 g/cm³, and 5.78 g/cm³, respectively.The refractive index of the composite fine particles was about 156, therefractive index being calculated from the amount of the daughterparticles in the composite fine particles. Incidentally, the amount ofthe daughter particles dispersed in and supported by aggregates of thematrix particles, which did not include the SiO₂ coating layer portion,was about 22.6% by volume.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.10 μm.

The composite fine particles before the water-repellent treatmentobtainable from the ethanol-containing cake of the composite fineparticles were diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 8.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region A, theultraviolet region B, and the ultraviolet region C, the wavelengths ofwhich were not longer than 350 nm. On the other hand, the composite fineparticles show extremely high light transmittance values in the entirevisible light region at a wavelength of from 400 to 800 nm, the lighttransmittance at 400 nm being 36%, and at 800 nm being 93%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 9

The preparation of the starting material liquid mixture and thedispersion treatment were carried out in the same manner as in Example2, to give a liquid dispersion containing the composite fine particlesof ZnO/SiO₂.

1500 g of ethanol, 16.26 g of tetraethoxysilane, and 3.9 ml of 1N-hydrochloric acid were mixed, and the contents were heated to 50° C.in a water bath. After the temperature of the resulting mixture reached50° C, the reaction mixture was matured for 2 hours and 30 minutes.After the maturation was completed, a mixed solution of 0.98 ml of 4N-sodium hydroxide aqueous solution and 50 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. Thereafter, amixed solution of 84.6 g of the above liquid dispersion containing theZnO/SiO₂ composite fine particles and 300 g of ethanol was addeddropwise to the neutralized solution. After the dropwise addition wascompleted, the contents were allowed to react with one another at 50°C., to thereby surface-coat the ZnO/SiO₂ composite fine particles withSiO₂. After the formation of the SiO₂ surface-coating was completed, 9.6g of a mixed solution of aluminum tri-sec-butoxide, isopropyl alcoholand ethanol solution (weight ratio: 1:9:90 (% by weight)) was addeddropwise to the resulting mixture, and the mixture was allowed to reactwith one another at 75° C. for 5 hours, to thereby further form an Al₂O₃ surface coating. All of the above steps were carried out understirring.

After the surface-coating treatment, a water-repellent treatment wascarried out by adding 0.66 g of dialkylphosphate ("DAP60H," manufacturedby Kao Corporation) to the liquid dispersion, and subjecting theresulting mixture containing the ZnO/SiO₂ composite fine particles to anultrasonic treatment at 75° C. for 1 hour.

After the water-repellent treatment, the liquid dispersion was subjectedto a reflux and dehydration treatment in the same manner as in Example5. After the reflux and dehydration treatment, 117.7 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the above liquid dispersion, followed bystirring and mixing. Thereafter, the resulting mixture was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol, isopropyl alcohol, and water, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that ZnO ultrafine particles (averageparticle diameter: about 0.01 μm) were dispersed in and supported byaggregates of SiO₂ ultrafine particles (average particle diameter: about0.01 μm). In other words, the composite fine particles were ZnO/SiO₂composite fine particles; matrix particles were the aggregates of SiO₂particles having a band gap energy of about 6.2 eV and a refractiveindex of about 1.46; and daughter particles comprise ZnO particleshaving a band gap energy of about 3.2 eV and a refractive index of about1.99.

The amount of the daughter particles in the above composite fineparticles was about 5.9% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andZnO were 2.27 g/cm³ and 5.78 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.49, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 9.6% by volume.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO, LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

The composite fine particles before the water-repellent treatmentobtainable from the ethanol-containing cake of the composite fineparticles were diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the ZnOparticles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.4 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 4.6 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 9.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region A, theultraviolet region B, and the ultraviolet region C, the wavelengths ofwhich were not longer than 350 nm. On the other hand, the composite fineparticles show high light transmittance values in the entire visiblelight region at a wavelength of from 400 to 800 nm, the lighttransmittance at 400 nm being 30%, and at 800 nm being 93%. Accordingly,the composite fine particles thus produced had a high transparency inthe visible light region and a high shielding ability in the ultravioletregion.

EXAMPLE 10

366.5 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight) and 39.9 g oftitanium oxide ultrafine particles ("IT-S," manufactured by IdemitsuKosan Co., Ltd.; amorphous-type) were mixed. To the mixture, water wasadded to make up a volume of one liter, yielding a starting materialliquid mixture. Specifically, the concentrations of SiO₂ and TiO₂ in thestarting material liquid mixture were 1.25 mol/liter and 0.5 mol/liter,respectively, and the amount of the daughter-and-matrix particle mixturecontained in the above starting material liquid mixture was about 11% byweight.

The above starting material liquid mixture thus prepared was subjectedto a dispersion treatment for 30 minutes using a disperser ("BIOMIXER,"manufactured by Nippon Seiki Co., Ltd.) at an agitation speed of 15000r.p.m., to give a liquid dispersion containing the composite fineparticles of TiO₂ /SiO₂.

After the surface-coating treatment, a water-repellent treatment wascarried out by adding 0.70 g of dialkylphosphate ("DAP60H," manufacturedby Kao Corporation) to the liquid dispersion, and subjecting theresulting mixture containing the TiO₂ /SiO₂ composite fine particles toan ultrasonic treatment at 75° C. for 1 hour.

After the water-repellent treatment, the liquid dispersion was subjectedto a reflux and dehydration treatment in the same manner as in Example5. After the reflux and dehydration treatment, 125.6 g of a silicone oil("KF96A," manufactured by Shin-Etsu Silicone Corporation; refractiveindex: 1.40) was added to the liquid dispersion followed by stirring andmixing. Thereafter, the resulting mixture was subjected to a toppingtreatment at 80° C. using a rotary evaporator to remove ethanol,isopropyl alcohol, and water, so that the composite fine particles werephase-transferred and dispersed in the silicone oil, to give a siliconeoil dispersion of the composite fine particles having a concentration ofthe composite fine particles of 10% by weight.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles were TiO₂particles having a band gap energy of about 3.4 eV and a refractiveindex of about 2.52.

The amount of the daughter particles in the above composite fineparticles was about 15.1% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 162, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 23.9% by volume.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.10 μm.

The composite fine particles before and after the water-repellenttreatment were dispersed in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After 0.1 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 4.9 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 10.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show high lighttransmittance values in the entire visible light region at a wavelengthof from 400 to 800 nm, the light transmittance at 400 nm being 43%, andat 800 nm being 83%. Accordingly, the composite fine particles thusproduced had a high transparency in the visible light region and a highshielding ability in the ultraviolet region.

EXAMPLE 11

268.3 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight) and 50.0 g oftitanium oxide ultrafine particles ("TTO-51(A)," manufactured byIshihara Sangyo Kaisha, Ltd.; rutile-type) were mixed. To the mixture,water was added to make up a volume of one liter, yielding a startingmaterial liquid mixture. Specifically, the concentrations of SiO₂ andTiO₂ in the starting material liquid mixture were 0.92 mol/liter and0.63 mol/liter, respectively, and the amount of the daughter-and-matrixparticle mixture contained in the above starting material liquid mixturewas about 11% by weight.

The above starting material liquid mixture thus prepared was subjectedto a dispersion treatment for 30 minutes using a dynomill ("KDL-PILOT,"manufactured by Willy A. Bachofen AG) under the conditions of anagitation speed of 3600 r.p.m. and a solution/media ratio of 600 cc/1200cc, for 8 minutes, the treatment procedure being repeated two moretimes, to give a liquid dispersion containing TiO₂ /SiO₂ ultrafineaggregates comprising TiO₂ as the daughter particles and SiO₂ as thematrix particles.

188 g of the above liquid dispersion, 1400 g of ethanol, and 32.6 g oftetraethoxysilane were mixed, and the contents were heated to 50° C. ina water bath. After the temperature of the resulting mixture reached 50°C., a mixed solution of 1.56 ml of 1 N-hydrochloric acid and 600 g ofethanol was added dropwise to the liquid dispersion. After the dropwiseaddition was completed, the contents were allowed to react with oneanother at 50° C. for 2 hours and 30 minutes, to thereby surface-coatthe composite fine particles with SiO₂. All of the above steps werecarried out under stirring.

After the topping treatment, the liquid dispersion was further subjectedto a topping treatment at 75° C. using a rotary evaporator to removeethanol and water, to thereby produce a liquid dispersion which wasconcentrated ten times that of the liquid dispersion before the toppingtreatment. Thereafter, 2782 g of isopropyl alcohol was added dropwise tothe concentrated liquid dispersion under stirring.

After the above topping treatment, the liquid dispersion was subjectedto a further topping treatment at 75° C. using a rotary evaporator toremove ethanol, isopropyl alcohol, and water, to thereby produce aliquid dispersion which was concentrated five times the liquiddispersion before the topping treatment.

After the concentration of the liquid dispersion was completed, a mixedsolution of 0.39 ml of 4 N-sodium hydroxide aqueous solution and 20 g ofethanol was added to the liquid dispersion to neutralize thehydrochloric acid. All of the above steps were carried out understirring.

While stirring the liquid dispersion obtained above, 600 g of a siliconeoil ("SH244," manufactured by Toray-Dow Corning Corporation; refractiveindex: 1.39) was added dropwise, and mixed with the liquid dispersion.Thereafter, a water-repellent treatment for the TiO₂ /SiO₂ compositefine particles was carried out by the steps of adding dropwise a mixedsolution of 0.6 g of an amino-modified silicone ("XF42-B0819,"manufactured by Toshiba Silicone Corporation; molecular weight: 10000;and amino equivalency: 1600) and 240 g of the silicone oil ("SH244" usedabove) and mixing the mixed solution with the resulting liquiddispersion; subjecting the resulting liquid dispersion to a toppingtreatment at 80° C. using a rotary evaporator to remove ethanol,isopropyl alcohol, and water; and adding dropwise a mixed solution of2.4 g of the amino-modified silicone ("XF42-B0819" used above) and 360 gof the silicone oil ("SH244" used above) and mixing the mixed solutionwith the liquid dispersion after the topping treatment.

The resulting liquid dispersion was subjected to a dispersion treatmentusing an ultrasonic disperser for one hour. Thereafter, the resultingmixture was subjected to a topping treatment at 80° C. using a rotaryevaporator to remove ethanol, isopropyl alcohol, water, and a siliconeoil, so that the composite fine particles were phase-transferred anddispersed in the silicone oil, to give a silicone oil dispersion of thecomposite fine particles having a concentration of the composite fineparticles of 35% by weight.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 22.3% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.74, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 35.0% by volume.

The composite fine particles before the water-repellent treatment werediluted in white vaseline (manufactured by Wako Pure ChemicalIndustries, Ltd.), so as to have a concentration of the TiO₂ particlesof 1% by weight in a mixture comprising white vaseline and the compositefine particles. Thereafter, the determination of color change wascarried out in the same manner as in Example 1. The above showed that nocolor change took place in the white vaseline, and that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After 0.057 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 9.943 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 11.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 57%, and at 800 nm being 95%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 12

The formation of the TiO₂ /SiO₂ composite fine particles and the SiO₂surface-coating treatment were carried out in the same manner as inExample 11.

After the coating step was completed, a mixed solution of 0.39 ml of 4N-sodium hydroxide aqueous solution and 20 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. All of the abovesteps were carried out under stirring.

While stirring the liquid dispersion obtained above, a water-repellenttreatment for the TiO₂ /SiO₂ composite fine particles was carried out bythe steps of adding dropwise a solution. comprising 3.0 g of anoxazoline-modified silicone ("OS96-20," manufactured by Kao Corporation)dissolved in 860 g of ethanol and mixing the mixed solution with theliquid dispersion.

After the water-repellent treatment, the liquid dispersion was subjectedto a topping treatment at 75° C. using a rotary evaporator to removeethanol and water, to thereby produce a liquid dispersion which wasconcentrated five times that of the liquid dispersion before the toppingtreatment.

While stirring the liquid dispersion obtained above, 575 g of a siliconeoil ("SH244," manufactured by Toray-Dow Corning Corporation; refractiveindex: 1.39) was added dropwise, and mixed with the liquid dispersion.Thereafter, the resulting liquid dispersion was subjected to a toppingtreatment at 80° C. using a rotary evaporator to remove ethanol andwater.

The resulting liquid dispersion was subjected to a dispersion treatmentusing a homogenizer for one hour. Thereafter, the resulting mixture wassubjected to a topping treatment at 80° C. using a rotary evaporator toremove ethanol, water, and a silicone oil, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 15% by weight.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 146; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 22.3% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.74, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 35.0% by volume.

The composite fine particles before the water-repellent treatment werediluted in white vaseline (manufactured by Wako Pure ChemicalIndustries, Ltd.), so as to have a concentration of the TiO₂ particlesof 1% by weight in a mixture comprising white vaseline and the compositefine particles. Thereafter, the determination of color change wascarried out in the same manner as in Example 1. The above showed that nocolor change took place in the white vaseline, and that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After 0.13 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 9.87 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 12.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 65%, and at 800 nm being 95%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 13

The formation of the TiO₂ /SiO₂ composite fine particles and the SiO₂surface-coating treatment were carried out in the same manner as inExample 11.

After the coating step was completed, a mixed solution of 0.39 ml of 4N-sodium hydroxide aqueous solution and 20 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. All of the abovesteps were carried out under stirring.

While stirring the liquid dispersion obtained above, a mixed solutioncomprising 0.6 g of a polyvinyl pyrrolidone ("K-30," for cosmetics,manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in 30 gof ethanol was added dropwise, and the mixed solution was blended withthe liquid dispersion. Thereafter, a water-repellent treatment for theTiO₂ /SiO₂ composite fine particles was carried out by the steps ofadding dropwise a mixed solution of 3.0 g of an oxazoline-modifiedsilicone ("OS96-20," manufactured by Kao Corporation) and 860 g ofethanol and mixing the mixed solution with the liquid dispersion.

The liquid dispersion thus obtained was subjected to a topping treatmentat 75° C. using a rotary evaporator to remove ethanol and water, tothereby produce a liquid dispersion which was concentrated five timesthat of the liquid dispersion before the topping treatment.

While stirring the liquid dispersion obtained above, 575 g of a siliconeoil ("SH244," manufactured by Toray-Dow Corning Corporation; refractiveindex: 139) was added dropwise, and mixed with the liquid dispersion.Thereafter, the resulting liquid dispersion was subjected to a toppingtreatment at 80° C. using a rotary evaporator to remove ethanol andwater.

The resulting liquid dispersion was subjected to a dispersion treatmentusing a homogenizer for one hour. Thereafter, the resulting mixture wassubjected to a topping treatment at 80° C. using a rotary evaporator toremove ethanol, water, and a silicone oil, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 25% by weight.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 22.3% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.74, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 35.0% by volume.

The composite fine particles before the water-repellent treatment werediluted in white vaseline (manufactured by Wako Pure ChemicalIndustries, Ltd.), so as to have a concentration of the TiO₂ particlesof 1% by weight in a mixture comprising white vaseline and the compositefine particles. Thereafter, the determination of color change wascarried out in the same manner as in Example 1. The above showed that nocolor change took place in the white vaseline, and that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After 0.08 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 9.92 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 13.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show extremely highlight transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 39%, and at 800 nm being 87%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 14

The formation of the TiO₂ /SiO₂ composite fine particles and the SiO₂surface-coating treatment were carried out in the same manner as inExample 11.

After the coating step was completed, a mixed solution of 0.39 ml of 4N-sodium hydroxide aqueous solution and 20 g of ethanol was added to thereaction mixture to neutralize the hydrochloric acid. All of the abovesteps were carried out under stirring.

While stirring the liquid dispersion obtained above, a mixed solutioncomprising 0.6 g of a polyvinyl pyrrolidone ("K-30," for cosmetics,manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in 30g ofethanol was added dropwise, and the mixed solution was blended with theliquid dispersion. Thereafter, a water-repellent treatment for the TiO₂/SiO₂ composite fine particles was carried out by the steps of addingdropwise a mixed solution of 3.0 g of an oxazoline-modified silicone("OS96-20," manufactured by Kao Corporation) and 860 g of ethanol andblending the mixed solution with the liquid dispersion.

The liquid dispersion obtained above was subjected to a drying treatmentat 80° C., to thereby dry the composite fine particles. The resultingpowder was pulverized twice using a mill ("A10," manufactured byIKA-Labourtechnik), to give the composite fine particles.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.08 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 22.3% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 1.74, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 35.0% by volume.

The composite fine particles before and after the water-repellenttreatment were diluted in white vaseline (manufactured by Wako PureChemical Industries, Ltd.), so as to have a concentration of the TiO₂particles of 1% by weight in a mixture comprising white vaseline and thecomposite fine particles. Thereafter, the determination of color changewas carried out in the same manner as in Example 1. The above showedthat no color change took place in the white vaseline, and that thecatalytic activities were substantially inhibited in the resultingcomposite fine particles.

After the water-repellent treatment, when the composite fine particleswere mixed with water, they showed a strong water repellent property.When the composite fine particles were mixed with a silicone oil("SH244," manufactured by Toray-Dow Corning Corporation; refractiveindex: 1.39), the composite fine particles were rapidly dispersed in thesilicone oil.

Ten mg of the composite fine particles having the above refractive indexwas dispersed in 10 g of the above silicone oil. The light transmittanceof the resulting liquid dispersion was evaluated in the same manner asin Example 1. The results are shown in FIG. 14.

In the figure, the light transmittance of the composite fine particleswas not more than 3% in the ultraviolet region B, the wavelength ofwhich was not longer than 300 nm, and it was substantially equal to 0%in the ultraviolet region C, the wavelength of which was not longer than260 nm. On the other hand, the composite fine particles show extremelyhigh light transmittance values in the entire visible light region at awavelength of from 400 to 800 nm, the light transmittance at 400 nmbeing 48%, and at 800 nm being 82%. Accordingly, the composite fineparticles thus produced had a high transparency in the visible lightregion and a high shielding ability in the ultraviolet region.

EXAMPLE 15

61.0 g of a silica sol ("ST-C," manufactured by Nissan ChemicalIndustries, Ltd.; SiO₂ concentration: 20.5% by weight) and 87.5 g oftitanium oxide ultrafine particles ("MT-600B," manufactured by TAYCACORPORATION; rutile-type) were mixed. To the mixture, water was added tomake up a volume of one liter, yielding a starting material liquidmixture. Specifically, the concentrations of SiO₂ and TiO₂ in thestarting material liquid mixture were 0.21 mol/liter and 1.10 mol/liter,respectively, and the amount of the daughter-and-matrix particle mixturecontained in the above starting material liquid mixture was about 10% byweight.

The above starting material liquid mixture thus prepared was subjectedto a pretreatment using a homogenizer ("T.K.-ROBOMICS," manufactured byTokushu Kika Kogyo Co., Ltd.) at 12000 r.p.m. for 90 minutes.Thereafter, while agitating at 7000 r.p.m., the pretreated startingmaterial liquid mixture was further subjected to a dispersion treatmentfor 30 minutes using a dynomill ("KDL-PILOT," manufactured by Willy A.Bachofen AG) under the conditions of an agitation speed of 3600 r.p.m.and a solution/media ratio of 600 cc/1200 cc, for 8 minutes, thetreatment procedure being repeated two more times, to give a liquiddispersion containing TiO₂ /SiO₂ ultrafine aggregates comprising TiO₂ asthe daughter particles and SiO₂ as the matrix particles.

188 g of the above liquid dispersion was subjected to a toppingtreatment using a rotary evaporator to remove water, to thereby producea liquid dispersion which was concentrated about three times that of theliquid dispersion before the topping treatment. Thereafter, whileagitating with a homogenizer ("T.K.-ROBOMICS" used above), the liquiddispersion was added dropwise to and dispersed in 1300 g of ethanol.Further, the resulting liquid dispersion was subjected to a dispersiontreatment using an ultrasonic disperser for 30 minutes. Subsequently, amixture comprising 32.6 g of tetraethoxysilane dissolved in 100 gethanol was added and mixed with the above liquid dispersion, and thecontents were heated to 50° C. in a water bath. After the temperature ofthe resulting mixture reached 50° C., a mixed solution of 1.56 ml of 1N-hydrochloric acid and 600 g of ethanol was added dropwise to theliquid dispersion. After the dropwise addition was completed, themixture was allowed to react with one another at 50° C. for 2 hours and30 minutes, to thereby surface-coat the composite fine particles withSiO₂. All of the above steps were carried out under stirring.

After the coating treatment was completed, a mixed solution of 0.39 mlof 4 N-sodium hydroxide aqueous solution and 20 g of ethanol was addedto the reaction mixture to neutralize the hydrochloric acid. All of theabove steps were carried out under stirring.

While stirring the liquid dispersion obtained above, a water-repellenttreatment for the TiO₂ /SiO₂ composite fine particles was carried out bythe steps of adding dropwise a mixed solution comprising 2.9 g of anoxazoline-modified silicone ("OS96-20," manufactured by Kao Corporation)dissolved in 842 g of ethanol and blending the mixed solution with theliquid dispersion.

The liquid dispersion thus obtained was further subjected to a toppingtreatment at 75° C. using a rotary evaporator to remove ethanol andwater, to thereby produce a liquid dispersion which was concentratedabout five times that of the liquid dispersion before the toppingtreatment.

While stirring the liquid dispersion obtained above, 582.8 g of asilicone oil ("SH244," manufactured by Toray-Dow Corning Corporation;refractive index: 1.39) was added dropwise, and mixed with the liquiddispersion. Thereafter, the resulting liquid dispersion was subjected toa topping treatment at 80° C. using a rotary evaporator to removeethanol and water.

The resulting liquid dispersion was subjected to a dispersion treatmentusing a homogenizer for one hour. Thereafter, the resulting mixture wassubjected to a topping treatment at 80° C. using a rotary evaporator toremove ethanol, water, and a silicone oil, so that the composite fineparticles were phase-transferred and dispersed in the silicone oil, togive a silicone oil dispersion of the composite fine particles having aconcentration of the composite fine particles of 25% by weight.

After the coating treatment, the liquid dispersion was subjected to asolid-liquid separation in the same manner as in Example 1, to give anethanol containing-cake of the composite fine particles. Thereafter, theparticle diameter of the composite fine particles before thewater-repellent treatment was measured by dispersing theethanol-containing cake of the composite fine particles in water andobtaining the particle diameter using a laser-doppler type particle sizeanalyzer ("DLS-700," manufactured by OTSUKA ELECTRONICS CO., LTD.). Itwas found that the average particle diameter, based on volume, was about0.10 μm.

After the water-repellent treatment, a cross section of the compositefine particles was observed by a transmission electron microscope(JEM-2000FX, manufactured by JEOL Ltd.) using an ultrathin sectioningmethod. Consequently, it was found that TiO₂ ultrafine particles(average particle diameter: about 0.01 μm) were dispersed in andsupported by aggregates of SiO₂ ultrafine particles (average particlediameter: about 0.01 μm). In other words, the composite fine particleswere TiO₂ /SiO₂ composite fine particles; matrix particles were theaggregates of SiO₂ particles having a band gap energy of about 6.2 eVand a refractive index of about 1.46; and daughter particles compriseTiO₂ particles having a band gap energy of about 3.3 eV and a refractiveindex of about 2.71.

The amount of the daughter particles in the above composite fineparticles was about 45.3% by volume, which was calculated based on thecompositional ratio of particles in the starting material liquid mixtureand the amount of SiO₂ coating, wherein particle densities of SiO₂ andTiO₂ were 2.27 g/cm³ and 3.84 g/cm³, respectively. The refractive indexof the composite fine particles was about 2.03, the refractive indexbeing calculated from the amount of the daughter particles in thecomposite fine particles. Incidentally, the amount of the daughterparticles dispersed in and supported by aggregates of the matrixparticles, which did not include the SiO₂ coating layer portion, wasabout 80.5% by volume.

The composite fine particles before the water-repellent treatment werediluted in white vaseline (manufactured by Wako Pure ChemicalIndustries, Ltd.), so as to have a concentration of the TiO₂ particlesof 1% by weight in a mixture comprising white vaseline and the compositefine particles. Thereafter, the determination of color change wascarried out in the same manner as in Example 1. The above showed that nocolor change took place in the white vaseline, and that the catalyticactivities were substantially inhibited in the resulting composite fineparticles.

After 0.046 g of the silicone oil dispersion of the composite fineparticles obtained above was diluted with 9.954 g of the silicone oil("KP96A" used above), the light transmittance of the resulting liquiddispersion was evaluated in the same manner as in Example 1. The resultsare shown in FIG. 15.

In the figure, the light transmittance of the composite fine particleswas substantially equal to 0% in the ultraviolet region B and theultraviolet region C, the wavelengths of which were not longer than 300nm. On the other hand, the composite fine particles show high lighttransmittance values in the entire visible light region at a wavelengthof from 400 to 800 nm, the light transmittance at 400 nm being 30%, andat 800 nm being 81%. Accordingly, the composite fine particles thusproduced had a high transparency in the visible light region and a highshielding ability in the ultraviolet region.

EXAMPLE 16 (Lotion)

    ______________________________________                           Amount    Ingredients            (weight %)    ______________________________________    Ethanol                30.0    Glycerol               5.0    Polyethylene glycol 1500                           4.0    Polyoxyethylene(20) oleyl ether                           1.0    Polyoxyethylene(30) hydrogenated castor oil                           0.5    Composite Fine Particles (Produced                           10.0    in Example 2)    Urocanic acid          2.0    Perfume                0.2    Distilled Water        Balance    ______________________________________

The lotion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 3.0 and PFA was 1.5. Itwas found that skin after lotion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 17 (Emulsion)

    ______________________________________                           Amount    Ingredients            (weight %)    ______________________________________    Cetanol                1.0    Squalane               2.0    Olive Oil              5.0    Octyl methoxycinnamate 4.0    Polyoxyethylene(10) hydrogenated castor oil                           1.0    Sorbitan monostearate  1.0    Dispersion Oil Containing Composite Fine                           25.0    Particles (Produced in Example 3)    Butyl p-hydroxybenzoate                           0.1    Methyl p-hydroxybenzoate                           0.1    Ethanol                3.0    Glycerol               2.0    1,3-Butylene glycol    2.0    Perfume                0.1    Distilled Water        Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 15.9 and PFA was 5.0. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 18 (Emulsion)

    ______________________________________                           Amount    Ingredients            (weight %)    ______________________________________    Dispersion Oil Containing Composite Fine                           30.0    Particles (Produced in Example 3)    Dimethylsiloxane-methyl (polyoxyethylene)-                           3.5    siloxane copolymer    Octamethyltetracyclosiloxane                           20.0    Organopolysiloxane B   1.0    Squalane               2.0    Octyldodecyl myristate 1.0    Butyl p-hydroxybenzoate                           0.1    Methyl p-hydroxybenzoate                           0.1    Glycerol               5.0    Perfume                0.1    Distilled Water        Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 2.5 and PFA was 1.2. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 19 (Cream)

    ______________________________________                           Amount    Ingredients            (weight %)    ______________________________________    Stearic Acid           2.0    Cetanol                1.0    Cholesterol            1.0    Squalane               5.0    Olive Oil              5.0    Octyl methoxycinnamate 4.0    Cetyl phosphate        0.5    Sorbitan monostearate  2.0    Polyoxyethylene(40) hydrogenated castor oil                           0.5    Composite Fine Particles (Produced                           15.0    in Example 4)    Titanium Oxide Fine Particles                           2.0    Butyl p-hydroxybenzoate                           0.1    Methyl p-hydroxybenzoate                           0.1    Glycerol               10.0    L-Arginine             0.3    Perfume                0.1    Distilled Water        Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 18.5 and PFA was 7.2. It wasfound that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 20 (Cream)

    ______________________________________                           Amount    Ingredients            (weight %)    ______________________________________    Dispersion Oil Containing Composite Fine                           20.0    Particles (Produced in Example 4)    Dimethylsiloxane-methyl (polyoxyethylene)                           4.0    siloxane copolymer    Methyl polysiloxane (6 cSt)                           5.0    2-Ethylhexyl p-methoxycinnamate                           3.0    4-Methoxy-4'-t-butylbenzoyl methane                           2.0    Octamethyl tetracyclosiloxane                           10.0    Squalane               2.0    Octyldodecyl myristate 1.0    Magnesium sulfate      0.5    Butyl p-hydroxybenzoate                           0.1    Methyl p-hydroxybenzoate                           0.1    Glycerol               6.0    Diglycerol             2.0    Polymethyl silsesquioxane powder                           4.0    Perfume                0.1    Distilled Water        Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 23.0 and PFA was 12.2. Itwas found that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 21 (Aerosol Cosmetics)

    ______________________________________                         Amount    Ingredients          (weight %)    ______________________________________    Triclosan            0.01    Aluminum hydroxychloride                         1.5    Talc                 1.0    Composite Fine Particles (Produced                         5.0    in Example 2)    Isopropyl myristate  2.0    Perfume              0.2    Propellant           Balance    ______________________________________

The aerosol cosmetics having the above composition were evaluated withrespect to SPF using an SPF analyzer. As a result, SPF was 1.4 and PFAwas 1.2. Also, it was found that the cosmetics had an excellentultraviolet shielding effect.

EXAMPLE 22 (Powdery Foundation)

    ______________________________________                              Amount    Ingredients               (weight %)    ______________________________________    (1)       Composite Fine Particles (Produced                                      10.0              in Example 3)    (2)       Fluorine Compound-Treated (*1) Mica                                      Balance    (3)       Fluorine Compound-Treated (*1) Talc                                      20.0    (4)       Fluorine Compound-Treated (*1)                                      8.0              Titanium Oxide    (5)       Fluorine Compound-Treated (*1) Iron Oxide                                      3.0              (Red, Yellow, Black)    (6)       Fluorine Compound-Treated (*1) Zinc Oxide                                      2.0              Fine Particles    (7)       Fluorine Compound-Treated (*1)                                      1.0              Titanium Oxide Fine Particles              (Average, Particle Diameter: 35 nm)    (8)       Fluorine Compound-Treated (*1)                                      10.0              Nylon Powder    (9)       Methyl polysiloxane (10 cSt)                                      4.0    (10)      Perfluoropolyether ("FOMBLIN HC-04,"                                      8.0              manufactured by AUSIMONT CO.)    (11)      Hydrogenated Oil (Synchrowax)                                      1.0    (12)      Octyl methoxycinnamate  1.0    (13)      Antiseptics, Perfume    1.0    ______________________________________     Note     (*1): Treatment was carried out by coating with 2% by weight of     perfluoroalkyl ethyl phosphate.

Ingredients (1) to (8) were blended in a Henschel mixer. Ingredients (9)to (13) subjected to blending and heating at 80° C. in advance wereadded to the mixture comprising the ingredients (1) to (8). Theresulting mixture was pulverized using a pulverizer. A given amount ofthe pulverized product was taken out on a metallic pan and pressed by apressing machine, to give a powdery foundation.

The resulting powdery foundation had remarkably advantageous effects inshielding ultraviolet light and had good spreadability, giving naturalfeeling after application.

EXAMPLE 23 (Two-Way Powdery Foundation)

    ______________________________________                            Amount    Ingredients             (weight %)    ______________________________________    (1)         Composite Fine Particles (Produced                                    20.0                in Example 2)    (2)         Silicone-Treated (*2) Mica                                    Balance    (3)         Silicone-Treated (*2) Talc                                    20.0    (4)         Silicone-Treated (*2) Titanium Oxide                                    9.0    (5)         Silicone-Treated (*2) Iron Oxide                                    4.0                Red, Yellow, Black)    (6)         Silicone-Treated (*2) Zinc Oxide                                    8.0                Fine Particles Coated with 30% by                weight of Nylon Powder    (7)         Methyl polysiloxane (10,000 cSt)                                    0.2    (8)         Methyl polysiloxane (6 cSt)                                    8.0    (9)         Hydrogenated Oil (Synchrowax)                                    1.0    (10)        Octyl methoxycinnamate                                    2.0    (11)        Antiseptics, Perfume                                    1.0    ______________________________________     Note     (*2): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

Ingredients (1) to (6) were blended in a Henschel mixer. Ingredients (7)to (11) subjected to blending and heating at 80° C. in advance wereadded to the mixture comprising the ingredients (1) to (6). Theresulting mixture was pulverized using a pulverizer. A given amount ofthe pulverized product was taken out on a metallic pan, and pressed by apressing machine, to give a two-way cake-foundation.

The resulting cake-foundation had remarkably advantageous effects inshielding ultraviolet light and had good spreadability, and naturalfeeling after application.

EXAMPLE 24 (Powdery Eye Shadow)

    ______________________________________                              Amount    Ingredients               (weight %)    ______________________________________    (1)       Dispersion Oil Containing Composite                                      11.0              Fine Particles (Produced in Example 5)    (2)       Lecithin-Treated (*3) Mica                                      Balance    (3)       Lecithin-Treated (*3) Titanated Mica                                      6.0    (4)       Silicone-Treated (*4) Ultramarine                                      8.0    (5)       Silicone-Treated (*4) Prussian blue                                      10.0    (6)       Silicone-Treated (*4) Iron Oxide                                      2.0              (Red, Yellow, Black)    (7)       Spherical Silicone Resin Powder                                      10.0              ("TOSPEARL 145," manufactured by Toshiba              Silicone Corpation)    (8)       Diisostearyl malate     3.0    (9)       Hydrogenated Oil (Synchrowax)                                      0.5    (10)      Vaseline                1.0    (11)      Antiseptics, Perfume    1.0    ______________________________________     Notes     (*3): Treatment was carried out by coating with 5% by weight of soybean     lecithin.     (*4): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

Ingredients (1) to (7) were blended in a Henschel mixer. Ingredients (8)to (11) subjected to blending and heating at 80° C. in advance wereadded to the mixture comprising the ingredients (1) to (7). Theresulting mixture was pulverized using a pulverizer. A given amount ofthe pulverized product was taken out on a metallic pan, and pressed by apressing machine, to give a powdery eye shadow.

The resulting powdery eye shadow had remarkably advantageous effects inshielding the ultraviolet light and had good spreadability, and providedgood coloring to the skin.

EXAMPLE 25 (Emulsion Type's Foundation)

    ______________________________________                             Amount    Ingredients              (weight %)    ______________________________________    (1)       Dispersion Oil Containing Composite                                     25.0              Fine Particles (Produced in Example 7)    (2)       Silicone-Treated (*5) Titanium Oxide                                     3.0    (3)       Silicone-Treated (*5) Iron Oxide                                     1.5              (Red, Yellow, Black)    (4)       Silicone-Treated (*5) Zinc Oxide                                     3.0              Fine Particles    (5)       Dimethylcyclopolysiloxane                                     10.0    (6)       Octyl methoxycinnamate 2.0    (7)       Dimethylsiloxane-methylpolyoxyethylene-                                     1.0              siloxane copolymer    (8)       Glycerol               2.0    (9)       Ethanol                10.0    (10)      Distilled water        Balance    ______________________________________     Notes     (*5): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

Ingredients (1) to (4) were blended in a Henschel mixer. Ingredients (5)to (7) were separately blended, and the mixture comprising theingredients (1) to (4) blended in advance was added to a mixturecomprising the ingredients (5) to (7), and the obtained mixture wasdispersed with a stirrer. A mixture comprising ingredients (8) to (10)was gradually added over a period of 30 minutes to the above dispersedmixture while stirring. The obtained mixture containing all ingredientslisted above was then emulsified by stirring with a homomixer for 10minutes. The obtained emulsion was defoamed, and then filled into abottle to give an emulsion type's foundation.

The resulting emulsion type's foundation had remarkably advantageouseffects in shielding ultraviolet light and had good spreadability, andnatural feeling after application.

EXAMPLE 26 (Lipstick)

    ______________________________________                            Amount    Ingredients             (weight %)    ______________________________________    (1)       Dispersion Oil Containing Composite                                    11.0              Fine Particles (Produced in Example 8)    (2)       Silicone-Treated (*6) Pigment Red 57-1                                    1.0    (3)       Silicone-Treated (*6) Pigment Red 57                                    2.0    (4)       Silicone-Treated (*6) Acid Yellow 23                                    1.0              Aluminum Lake    (5)       Silicone-Treated (*6) Titanium Oxide                                    1.0    (6)       Paraffin wax          5.0    (7)       Candelilla wax        10.0    (8)       Carnauba wax          9.0    (9)       Isopropyl isopalmitate                                    20.0    (10)      Isononyl isononanate  15.0    (11)      Isostearyl malate     20.0    (12)      Methyl polysiloxane (1000 cSt)                                    5.0    ______________________________________     Note     (*6): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

Ingredients (1) to (12) were heated to 80° C. and blended to give ahomogeneous mixture, and the obtained mixture was cooled to atemperature of 30° C. The cooled mixture was sufficiently blended with atriple roller, and then reheated to 80° C. The obtained mixture wascasted into a mold and then solidified by cooling to give a lipstick.

The resulting lipstick had remarkably advantageous effects in shieldingultraviolet light and had good spreadability, thus providing goodcoloring to the lip. Incidentally, in the case where the oil used forthe dispersion oil containing the composite fine particles produced inExample 8 was changed from a silicone oil to an ester oil (diisostearylmalate: "COSMOL 222," manufactured by The Nisshin Oil Mills, Ltd.),substantially the same level of the ultraviolet shielding effects can beobtained.

In the following Examples and Comparative Examples, the following fivekinds of ether-modified silicones were used, but the ether-modifiedsilicones in the present invention are not limited thereto.

(i) Ether-modified Silicone A:

Dimethylsiloxane-methyl (polyoxyethylene)siloxane copolymer representedby the general formula (3), with proviso that R¹¹ and R¹² both stand formethyl groups; R¹³ stands for H(OC₃ H₆)_(b) (OC₂ H₄)_(a) O(CH₂)_(p) --,wherein "a" is a number of from 7 to 15, "b" is equal to 0, and "p" isequal to 3; "m" is a number of from 50 to 100; and "n" is a number offrom 1 to 5.

(ii) Ether-modified Silicone B:

Dimethylsiloxane-methyl (polyoxyethylene)siloxane copolymer representedby the general formula (3), with proviso that R¹¹ and R¹² both stand formethyl groups; R¹³ stands for H(OC₃ H₆)_(b) (OC₂ H₄)_(a) O(CH₂)_(p) --,wherein "a" is a number of from 2 to 5, "b" is equal to 0, and "p" isequal to 3; "m" is a number of from 20 to 30; and "n" is a number offrom 2 to 5.

(iii) Ether-modified Silicone C:

Dimethylsiloxane-methyl (polyoxyethylene)siloxane copolymer representedby the general formula (3), with proviso that R¹¹ and R¹² both stand formethyl groups; R¹³ stands for H(OC₃ H₆)_(b) (OC₂ H₄)_(a) O(CH₂)_(p) --,wherein "a" is equal to 0, "b" is a number of from 7 to 13, and "p" isequal to 3; "m" is a number of from 4 to 10; and "n" is a number of from1 to 6.

(iv) Ether-modified Silicone D:

Laurylmethycone copolyol represented by the general formula (4), whereinR²¹ stands for a methyl group; R²² stands for a dodecyl group; R²³stands for --(OC₂ H₄)_(q) (OC₃ H₆)_(r) --OH, wherein "q" is a number offrom 10 to 30, and "r" is a number of from 10 to 30; Q stands for atrimethylene group; "x" is equal to 0; "y" is a number of from 30 to 70;and "z" is a number of from 1 to 6.

(v) Ether-modified Silicone E:

Alkylglycerylether-modified silicones represented by the general formula(5), with proviso that at least one of R³⁴ stands for --A--OCH₂CH(OR⁴¹)CH₂ OR⁴², wherein "A" stands for C₁₁ H₂₃ ; and R⁴¹ and R⁴² bothstand for a hydrogen atom; "s" and "t" are numbers where the sum thereofequals to 60; "u" is equal to 40.

EXAMPLE 27 (Emulsion)

    ______________________________________                             Amount    Ingredients              (weight %)    ______________________________________    (1)        Cetanol               1.0    (2)        Squalane              2.0    (3)        Jojoba oil            4.0    (4)        Octyl methoxycinnamate                                     4.0    (5)        Polyoxyethylene(10) hydrogenated                                     1.0               castor oil    (6)        Sorbitan monostearate 1.0    (7)        Dispersion Oil Containing Composite Fine                                     25.0               Particles (Produced in Example 12)    (8)        Butyl p-hydroxybenzoate                                     0.1    (9)        Methyl p-hydroxybenzoate                                     0.1    (10)       Ethanol               3.0    (11)       Glycerol              4.0    (12)       Perfume               0.05    (13)       Distilled water       Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 15.9 and PFA was 6.2. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 28 (Cream)

    ______________________________________                             Amount    Ingredients              (weight %)    ______________________________________    (1)        Cetanol               1.0    (2)        Stearic Acid          2.0    (3)        Cholesterol           1.0    (4)        Squalane              5.0    (5)        Jojoba oil            4.0    (6)        Octyl methoxycinnamate                                     4.0    (7)        Polyoxyethylene(40) hydrogenated                                     1.0               castor oil    (8)        Sorbitan monostearate 2.0    (9)        Dispersion Oil Containing Composite Fine                                     15.0               Particles (Produced in Example 13)    (10)       Butyl p-hydroxybenzoate                                     0.1    (11)       Methyl p-hydroxybenzoate                                     0.1    (12)       Ethanol               3.0    (13)       Glycerol              10.0    (14)       Perfume               0.05    (15)       Distilled water       Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer As a result, SPF was 15.7 and PFA was 6.3. It wasfound that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 29 (Emulsion Type's Foundation)

    ______________________________________                             Amount    Ingredients              (weight %)    ______________________________________    (1)       Dispersion Oil Containing Composite                                     25.0              Fine Particles (Produced in Example 13)    (2)       Silicone-Treated (*7) Titanium Oxide                                     3.0    (3)       Silicone-Treated (*7) Iron Oxide                                     1.5              (Red, Yellow, Black)    (4)       Silicone-Treated (*7) Zinc Oxide                                     3.0              Fine Particles    (5)       Dimethylcyclopolysiloxane                                     10.0    (6)       Octyl methoxycinnamate 2.0    (7)       Dimethylsiloxane-methylpolyoxyethylene-                                     1.0              siloxane copolymer    (8)       Glycerol               2.0    (9)       Ethanol                10.0    (10)      Distilled water        Balance    ______________________________________     Notes     (*7): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

The emulsion types foundation prepared above was evaluated with respectto SPF and PFA in the same manner as in Example 1. As a result,substantially the same or higher level of the ultraviolet shieldingability when compared to that of Example 1 was achieved.

EXAMPLE 30 (Lipstick)

    ______________________________________                            Amount    Ingredients             (weight %)    ______________________________________    (1)        Dispersion Oil Containing Composite                                    11.0               Fine Particles (Produced in Example 13)    (2)        Silicone-Treated (*8) Pigment Red 57-1                                    1.0    (3)        Silicone-Treated (*8) Pigment Red 57                                    2.0    (4)        Silicone-Treated (*8) Acid Yellow 23                                    1.0               Aluminum Lake    (5)        Silicone-Treated (*8) Titanium Oxide                                    1.0    (6)        Paraffin wax         5.0    (7)        Candelilla wax       10.0    (8)        Carnauba wax         9.0    (9)        Isopropyl isopalmitate                                    20.0    (10)       Isononyl isononanate 15.0    (11)       Isostearyl malate    20.0    (12)       Methyl polysiloxane (1000 cSt)                                    5.0    ______________________________________     Note     (*8): Treatment was carried out by coating with 2% by weight of     methylhydrogenpolysiloxane.

The lipstick prepared above was evaluated with respect to SPF and PFA inthe same manner as in Example 1. As a result, substantially the same orhigher level of the ultraviolet shielding ability when compared to thatof Example 1 was achieved.

EXAMPLE 31 (Water-in-Oil Type Cream)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Dispersion Oil Containing Composite                                   25.0            Fine Particles (Produced in Example 13)    (2)     Ether-modified silicone A ("SH-3775C,"                                   2.0            manufactured by Toray-Dow Corning)    (3)     α-Monomethyl-branched isostearyl                                   2.0            glyceryl ether    (4)     Methyl polysiloxane (6 cSt)                                   5.0    (5)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (6)     Magnesium sulfate      0.5    (7)     Glycerol               5.0    (8)     Butyl p-hydroxybenzoate                                   0.1    (9)     Methyl p-hydroxybenzoate                                   0.1    (10)    Perfume                0.05    (11)    Distilled water        Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 19.6 and PFA was 9.2. It wasfound that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 32 (Water-in-Oil Type Emulsion)

    ______________________________________                              Amount    Ingredients               (weight %)    ______________________________________    (1)   Dispersion Oil Containing Composite                                  25.0          Fine Particles (Produced in Example 13)    (2)   Ether-modified silicone C ("FZ-2110C,"                                  1.5          manufactured by Nippon Unicar)    (3)   Ether-modified silicone B ("KF-6015,"                                  1.5          manufactured by Shin-Etsu Silicone)    (4)   Ether-modified silicone D ("DC Q2-2500,"                                  1.0          manufactured by Toray-Dow Corning)    (5)   Methyl polysiloxane (6 cst)                                  5.0    (6)   Decamethyl cyclopentasiloxane                                  5.0    (7)   2-Ethylhexyl p-methoxycinnamate                                  3.0    (8)   Squalane                2.0    (9)   Glycerol                3.0    (10)  Butyl p-hydroxybenzoate 0.1    (11)  Methyl p-hydroxybenzoate                                  0.1    (12)  Perfume                 0.05    (13)  Distilled water         Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 19.2 and PFA was 8.7. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 33 (Water-in-Oil Type Cream)

    ______________________________________                              Amount    Ingredients               (weight %)    ______________________________________    (1)     Dispersion Oil Containing Composite                                  20.0            Fine Particies (Produced in Example 12)    (2)     Ether-modified silicone E                                  1.5    (3)     Ether-modified silicone B ("KF-6015,"                                  0.5            manufactured by Shin-Etsu Silicone)    (4)     Methyl polysiloxane (6 cSt)                                  5.0    (5)     Decamethyl cyclopentasiloxane                                  5.0    (6)     2-Ethylhexyl p-methoxycinnamate                                  3.0    (7)     4-Methoxy-4'-t-butylbenzoylmethane                                  2.0    (8)     Squalane              2.0    (9)     Magnesium sulfate     0.5    (10)    Glycerol              5.0    (11)    Butyl p-hydroxybenzoate                                  0.1    (12)    Methyl p-hydroxybenzoate                                  0.1    (13)    Perfume               0.05    (14)    Distilled water       Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 15.8 and PFA was 10.2. Itwas found that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 34 (Water-in-Oil Type Emulsion)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Dispersion Oil Containing Composite                                   5.0            Fine Particles (Produced in Example 12)    (2)     Ether-modified silicone B ("KF-6015,"                                   0.5            manufactured by Shin-Etsu Silicone)    (3)     Ether-modified silicone A ("SH-3775C,"                                   1.0            manufactured by Toray-Dow Corning)    (4)     Methyl polysiloxane (6 cst)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   5.0    (6)     4-Methoxy-4'-t-butylbenzoylmethane                                   2.0    (7)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (8)     Squalane               2.0    (9)     Glycerol               3.0    (10)    Butyl p-hydroxybenzoate                                   0.1    (11)    Methyl p-hydroxybenzoate                                   0.1    (12)    Perfume                0.05    (13)    Distilled water        Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 14.9 and PFA was 10.8.It was found that skin after emulsion application was free fromunnatural whitening, showing that the cosmetics had an excellentultraviolet shielding effect.

EXAMPLE 35 (Water-in-Oil Type Cream)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Composite Fine Particles (Produced                                   5.0            in Example 12)    (2)     Ether-modified silicone A ("SH-3775C,"                                   2.0            manufactured by Toray-Dow Corning)    (3)     α-Monomethyl-branched isostearyl                                   2.0            glyceryl ether    (4)     Methyl polysiloxane (6 cst)                                   5.0    (5)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (6)     Magnesium sulfate      0.5    (7)     Glycerol               5.0    (8)     Butyl p-hydroxybenzoate                                   0.1    (9)     Methyl p-hydroxybenzoate                                   0.1    (10)    Perfume                0.05    (11)    Distilled water        Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 17.5 and PFA was 6.9. It wasfound that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 36 (Water-in-Oil Type Emulsion)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Composite Fine Particles (Produced                                   5.0            in Example 12)    (2)     Ether-modified silicone C ("FZ-2110C,"                                   1.5            manufactured by Nippon Unicar)    (3)     Ether-modified silicone B ("KF-6015,"                                   1.5            manufactured by Shin-Etsu Silicone)    (4)     Ether-modified silicone D ("DC Q2-2500,"                                   1.0            manufactured by Toray-Dow Corning)    (5)     Methyl polysiloxane (6 cSt)                                   5.0    (6)     Dedamethyl cyclopentasiloxane                                   5.0    (7)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (8)     Squalane               2.0    (9)     Glycerol               3.0    (10)    Butyl p-hydroxybenzoate                                   0.1    (11)    Methyl p-hydroxybenzoate                                   0.1    (12)    Perfume                0.05    (13)    Distilled water        Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 16.8 and PFA was 6.8. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 37 (Water-in-Oil Type Cream)

    ______________________________________                              Amount    Ingredients               (weight %)    ______________________________________    (1)     Dispersion Oil Containing Composite                                  5.0            Fine Particles (Produced in Example 3)    (2)     Ether-modified silicone E                                  1.5    (3)     Ether-modified silicone B ("KF-6015,"                                  0.5            manufactured by Shin-Etsu Silicone)    (4)     Methyl polysiloxane (6 cSt)                                  5.0    (5)     Decamethyl cyclopentasiloxane                                  5.0    (6)     2-Ethylhexyl p-methoxycinnamate                                  3.0    (7)     4-Methoxy-4'-t-butylbenzoylmethane                                  2.0    (8)     Squalane              2.0    (9)     Magnesium sulfate     0.5    (10)    Glycerol              5.0    (11)    Butyl p-hydroxybenzoate                                  0.1    (12)    Methyl p-hydroxybenzoate                                  0.1    (13)    Perfume               0.05    (14)    Distilled water       Balance    ______________________________________

The cream having the above composition was evaluated with respect to SPFusing an SPF analyzer. As a result, SPF was 18.5 and PFA was 9.6. It wasfound that skin after cream application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

EXAMPLE 38 (Water-in-Oil Type Emulsion)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Dispersion Oil Containing Composite                                   5.0            Fine Particles (Produced in Example 4)    (2)     Ether-modified silicone B ("KF-6015,"                                   0.5            manufactured by Shin-Etsu Silicone)    (3)     Ether-modified silicone A ("SH-3775C,"                                   1.0            manufactured by Toray-Dow Corning)    (4)     Methyl polysiloxane (6 cst)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   5.0    (6)     4-Methoxy-4'-t-butylbenzoylmethane                                   2.0    (7)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (8)     Squalane               2.0    (9)     Glycerol               3.0    (10)    Butyl p-hydroxybenzoate                                   0.1    (11)    Methyl p-hydroxybenzoate                                   0.1    (12)    Perfume                0.05    (13)    Distilled water        Balance    ______________________________________

The emulsion having the above composition was evaluated with respect toSPF using an SPF analyzer. As a result, SPF was 18.7 and PFA was 9.7. Itwas found that skin after emulsion application was free from unnaturalwhitening, showing that the cosmetics had an excellent ultravioletshielding effect.

COMPARATIVE EXAMPLE 1 (Water-in-Oil Type Cream)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Titanium oxide fine particles                                   5.0            ("TTO-55(C)," manufactured by            Ishihara Sangyo Kaisha, Ltd.; average            particle diameter: 30 to 50 μm)    (2)     Ether-modified silicone A ("SH-3775C,"                                   2.0            manufactured by Toray-Dow Corning)    (3)     α-Monomethyl-branched isostearyl                                   2.0            glyceryl ether    (4)     Methyl polysiloxane (6 cSt)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   20.0    (6)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (7)     Magnesium sulfate      0.5    (8)     Glycerol               5.0    (9)     Butyl p-hydroxybenzoate                                   0.1    (10)    Methyl p-hydroxybenzoate                                   0.1    (11)    Perfume                0.05    (12)    Distilled water        Balance    ______________________________________

COMPARATIVE EXAMPLE 2 (Water-in-Oil Type Cream)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Titanium oxide fine particles                                   5.0            ("TTO-51(C)," manufactured by            Ishihara Sangyo Kaisha, Ltd.; average            particle diameter: 10 to 30 pm)    (2)     Ether-modified silicone A ("SH-3775C,"                                   2.0            manufactured by Toray-Dow Corning)    (3)     α-Monomethyl-branched isostearyl                                   2.0            glyceryl ether    (4)     Methyl polysiloxane (6 cSt)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   20.0    (6)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (7)     Magnesium sulfate      0.5    (8)     Glycerol               5.0    (9)     Butyl p-hydroxybenzoate                                   0.1    (10)    Methyl p-hydroxybenzoate                                   0.1    (11)    Perfume                0.05    (12)    Distilled water        Balance    ______________________________________

COMPARATIVE EXAMPLE 3 (Water-in-Oil Type Emulsion)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Titanium oxide fine particles                                   5.0            ("TTO-55(C)," manufactured by            Ishihara Sangyo Kaisha, Ltd.; average            particle diameter: 30 to 50 μm)    (2)     Ether-modified silicone B ("KF-6015,"                                   0.5            manufactured by Shin-Etsu Silicone)    (3)     Ether-modified silicone A ("SH-3775C,"                                   1.0            manufactured by Toray-Dow Corning)    (4)     Methyl polysiloxane (6 cSt)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   5.0    (6)     4-Methoxy-4'-t-butylbenzoylmethane                                   2.0    (7)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (8)     Squalane               2.0    (9)     Glycerol               3.0    (10)    Butyl p-hydroxybenzoate                                   0.1    (11)    Methyl p-hydroxybenzoate                                   0.1    (12)    Perfume                0.05    (13)    Distilled water        Balance    ______________________________________

COMPARATIVE EXAMPLE 4 (Water-in-Oil Type Emulsion)

    ______________________________________                               Amount    Ingredients                (weight %)    ______________________________________    (1)     Titanium oxide fine particles                                   5.0            ("TTO-51(C)," manufactured by            Ishihara Sangyo Kaisha, Ltd.; average            particle diameter: 10 to 30 μm)    (2)     Ether-modified silicone B ("KF-6015,"                                   0.5            manufactured by Shin-Etsu Silicone)    (3)     Ether-modified silicone A ("SH-3775C,"                                   1.0            manufactured by Toray-Dow Corning)    (4)     Methyl polysiloxane (6 cSt)                                   5.0    (5)     Decamethyl cyclopentasiloxane                                   5.0    (6)     4-Methoxy-4'-t-butylbenzoylmethane                                   2.0    (7)     2-Ethylhexyl p-methoxycinnamate                                   3.0    (8)     Squalane               2.0    (9)     Glycerol               3.0    (10)    Butyl p-hydroxybenzoate                                   0.1    (11)    Methyl p-hydroxybenzoate                                   0.1    (12)    Perfume                0.05    (13)    Distilled water        Balance    ______________________________________

The ultraviolet shielding effects and changes in appearance before andafter skin application were evaluated for Example 31, ComparativeExample 1, and Comparative Example 2. The results are shown in Table 1.Also, the ultraviolet shielding effects and changes in appearance(transparency) before and after skin application were evaluated forExample 34, Comparative Example 3, and Comparative Example 4. Theresults are shown in Table 2.

The ultraviolet shielding effect was evaluated by ultraviolet shieldingindices and PCB values. Here, the ultraviolet shielding indices werecalculated by the following equation using Hartley white guinea pigs.##EQU1##

In addition, PFB values were obtained by a UVB method disclosed in J.Soc. Cosmet. Chem. Jpn. 28 (3), pp.254-261 (1994).

The changes in appearance before and after skin application wereevaluated by carrying out white-color calibration using a color-andcolor difference meter (chromatic color-and color difference meter"CR-310," manufactured by Minolta Camera Co., Ltd.), and calculating thechanges (ΔE*_(ab)) of the color-and-color difference before application(L*⁰, a*⁰, b*⁰) and the color-and-color difference after application(L*¹, a*¹, b*¹). Here, ΔE*_(ab) is a value defined according to JIS Z8729-1980, which was calculated by the following equations:

    ΔL*=(L*.sup.1 -L*.sup.0)

    Δa*=(a*.sup.1 -a*.sup.0)

    Δb*=(b*.sup.1 -b*.sup.0) ##EQU2##

Here, L*⁰, a*⁰, b*⁰, L*₁, a*¹, and b*¹ were defined as follows:

L*⁰ : L* value (psychometric lightness) before skin application;

a*⁰ : a* value (psychometric chroma coordinates) before skinapplication;

b*⁰ : b* value (psychometric chroma coordinates) before skinapplication;

L*¹ : L* value after skin application;

a*¹ : a* value after skin application; and

b*¹ : b* value after skin application.

Also, SPF and PFA values were obtained by using an analyzer "SPF-290"(manufactured by The Optometrics Groups) and following the basicmeasurement technique according to the description given in the attachedmanual. Incidentally, PFA was indicated as an "Average UVA protectionfactor" in the attached manual.

                  TABLE 1    ______________________________________                       Comparative                                 Comparative            Example 31 Example 1 Example 2    ______________________________________    SPF       19.6         19.2      7.5    PFA       9.2          8.9       3.2    Ultraviolet              7.5          6.5       3.0    Shielding    Index    Change in 0.9          7.8       2.2    Appearance    (Δ E* ab)    ______________________________________

                  TABLE 2    ______________________________________                       Comparative                                 Comparative            Example 34 Example 3 Example 4    ______________________________________    SPF       14.9         15.7      7.3    PFA       10.8         11.0      4.0    Ultraviolet              6.5          6.7       2.8    Shielding    Index    Change in 0.6          7.4       1.9    Appearance    Δ E* ab)    ______________________________________

As is clear from the above results, it was found that the productsobtained in Examples of the present invention had remarkably highultraviolet shielding effects and high transparency.

INDUSTRIAL APPLICABILITY

When dispersed in a liquid or solid medium, the composite fine particlesof the present invention show high light transmittance in the visiblelight region and also high shielding ability in the ultraviolet lightregion by the scattering ability and the absorption ability of thedaughter particles. In addition, although the daughter particles havinghigh catalytic activities are present in the inner portion of the matrixparticles or the surface thereof, by coating the surface of thecomposite fine particles comprising the daughter particles and thematrix particles with inorganic materials having substantially nocatalytic activities, the catalytic activities owned by the daughterparticles do not cause to deteriorate the dispersant or the medium whichis present in the periphery of the composite fine particles. In otherwords, the composite fine particles of the present invention arecomposites of ultrafine particles having ultraviolet shielding abilityand the surface of the composite fine particles are coated by theinorganic materials having substantially no catalytic activities, sothat the resulting composite fine particles have substantially nocatalytic activities, while retaining such optical properties inherentlyowned by the ultrafine particles as high transparency in the visiblelight region and high shielding ability in the ultraviolet light region,the above properties being stably exhibited in an easy-to-handle, fineparticle size. Further, in the case where the composite fine particlesof the present invention are subjected to a water-repellent treatment,they can stably and uniformly disperse when incorporated in water-in-oiltype cosmetics or oil-in-water type cosmetics, so that the deteriorationof cosmetics base materials are not likely to be caused. When thecomposite fine particles of the present invention are incorporated incosmetics, the resulting cosmetics have good smoothness on skin,excellent spreading on skin without unevenness, and excellenttransparency, and are free from unnatural whitening, thereby havingexcellent ultraviolet shielding ability, and have excellent safety andstability. Further, since the composite fine particles of the presentinvention have excellent transparency, substantially no coloring of thecosmetics are lost, and the degree of freedom of the amount of thecomposite fine particles which can be formulated to cosmetics is alsohigh.

The present invention being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

We claim:
 1. Ultraviolet shielding composite fine particles havingtransparency in a visible light region, comprising:(a) matrix particlescomprising an aggregate of primary particles having an average particlediameter of from 0.001 to 0.3 μm, said aggregate being formed while theprimary particles retain their shapes; and (b) daughter particles havingan average particle diameter of from 0.001 to 0.1 μm, said daughterparticles being dispersed in and supported by said matrix particles,wherein said daughter particles have a smaller band gap energy than theparticles constituting said matrix particles and are capable ofabsorbing ultraviolet light, and wherein the surface of said ultravioletshielding composite fine particles is coated with an inorganic material,thereby showing substantially no catalytic activities.
 2. Theultraviolet shielding composite fine particles according to claim 1,wherein said particles constituting the matrix particles have a band gapenergy of from 3 to 9 eV.
 3. The ultraviolet shielding composite fineparticles according to claim 1, wherein the difference between the bandgap energies of the daughter particles and the particles constitutingthe matrix particles is not less than 0.2 eV.
 4. The ultravioletshielding composite fine particles according to claim 1, wherein saiddaughter particles are dispersed in and supported by said matrixparticles in an amount of from 0.1 to 85% by volume.
 5. The ultravioletshielding composite fine particles according to claim 1, wherein theaverage particle diameter of the ultraviolet shielding composite fineparticles is not more than 0.5 μm.
 6. The ultraviolet shieldingcomposite fine particles according to claim 1, wherein the averagerefractive index of the ultraviolet shielding composite fine particlesis from 1.3 to 2.5.
 7. The ultraviolet shielding composite fineparticles according to claim 1, wherein said particles constituting thematrix particles are selected from the group consisting of metal oxides,fluorine compounds, and mixtures thereof.
 8. The ultraviolet shieldingcomposite fine particles according to claim 7, wherein said metal oxideis selected from the group consisting of SiO₂, Al₂ O₃, and a mixturethereof.
 9. The ultraviolet shielding composite fine particles accordingto claim 1, wherein said daughter particles are selected from the groupconsisting of TiO₂, ZnO, CeO₂, SiC, SnO₂, WO₃, BaTiO₃, CaTiO₃, SrTiO₃,and mixtures thereof.
 10. The ultraviolet shielding composite fineparticles according to claim 1, wherein the inorganic material is ametal oxide.
 11. The ultraviolet shielding composite fine particlesaccording to claim 10, wherein the metal oxide used for the inorganicmaterial is selected from the group consisting of SiO₂, Al₂ O₃, and amixture thereof.
 12. The ultraviolet shielding composite fine particlesaccording to claim 1, wherein the surface of sa id composite fineparticles is further treated by a water-repellant.
 13. The ultravioletshielding composite fine particles according to claim 1, wherein saidultraviolet shielding composite fine particles have a lighttransmittance of not less than 80% at a wavelength of 800 nm, a lighttransmittance of not less than 20% at a wavelength of 400 nm, and alight transmittance of not more than 5% at least at one wavelengthwithin the range from 380 nm to 300 nm, the light transmittance beingdetermined by suspending said composite fine particles in a mediumhaving substantially the same refractive index level as the compositefine particles, and measuring with an ultraviolet-visible lightspectrophotometer using an optical cell having an optical path length of1 mm.
 14. The ultraviolet shielding composite fine particles accordingto claim 1, obtained by the steps of:(a) preparing a liquid mixturecomprising:(i) starting materials for matrix particles which are presentin one or more forms selected from the group consisting of solscontaining particles constituting matrix particles and powders of thematrix particles, the matrix particles having a primary particle with anaverage particle diameter of from 0.001 to 0.3 μm; and (ii) startingmaterials for daughter particles which are present in one or more formsselected from the group consisting of sols containing daughter particlesand powders of the daughter particles, the daughter particles having aprimary particle with an average particle diameter of from 0.001 to 0.1μm, and treating the liquid mixture in a mill and/or an apparatus forhigh-pressure dispersion, to thereby produce composite fine particleswherein the daughter particles and the matrix particles are aggregated;(b) coating the composite fine particles obtained in step (a) with aninorganic material; (c) subjecting the composite fine particles coatedwith the inorganic material obtained in step (b) to a water-repellenttreatment; and (d) drying and/or pulverizing the composite fineparticles subjected to the water-repellent treatment obtained in step(c).
 15. A dispersion oil agent of the ultraviolet shielding compositefine particles as defined in claim 1, obtained by the steps of:(a)preparing a liquid mixture comprising:(i) starting materials for matrixparticles which are present in one or more forms selected from the groupconsisting of sols containing particles constituting matrix particlesand powders of the matrix particles, the matrix particles having aprimary particle with an average particle diameter of from 0.001 to 0.3μm; and (ii) starting materials for daughter particles which are presentin one or more forms selected from the group consisting of solscontaining daughter particles and powders of the daughter particles, thedaughter particles having a primary particle with an average particlediameter of from 0.001 to 0.1 μm, and treating the liquid mixture in amill and/or an apparatus for high-pressure dispersion, to therebyproduce composite fine particles wherein the daughter particles and thematrix particles are aggregated; (b) coating the composite fineparticles obtained in step (a) with an inorganic material; (c)subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and (d')dispersing in an oil agent the composite fine particles subjected to thewater-repellent treatment obtained in step (c).
 16. A method forproducing the ultraviolet shielding composite fine particles comprisingdaughter particles being dispersed in and supported by said matrixparticles, the ultraviolet shielding composite fine particles havingsubstantially no catalytic activities and having transparency in avisible light region, obtained by the steps of:(a) preparing a liquidmixture comprising (i) starting materials for matrix particles which arepresent in one or more forms selected from the group consisting of solscontaining particles constituting matrix particles and powders of thematrix particles, the matrix particles having a primary particle with anaverage particle diameter of from 0.001 to 0.3 μm; and (ii) startingmaterials for daughter particles which are present in one or more formsselected from the group consisting of sols containing daughter particlesand powders of the daughter particles, the daughter particles having aprimary particle with an average particle diameter of from 0.001 to 0.1μm, and treating the liquid mixture in a mill and/or an apparatus forhigh-pressure dispersion, to thereby produce composite fine particleswherein the daughter particles and the matrix particles are aggregated;and (b) coating the composite fine particles obtained in step (a)with-an inorganic material.
 17. The method according to claim 16,further comprising, subsequent to said step (b):(c) subjecting thecomposite fine particles coated with the inorganic material obtained instep (b) to a water-repellent treatment.
 18. The method according toclaim 17, further comprising, subsequent to said step (c):(d) dryingand/or pulverizing the composite fine particles subjected to thewater-repellent treatment obtained in step (c).
 19. A method forproducing a dispersion oil agent of the ultraviolet shielding compositefine particles comprising daughter particles being dispersed in andsupported by said matrix particles, the ultraviolet shielding compositefine particles having substantially no catalytic activities and havingtransparency in a visible light region, obtained by the steps of:(a)preparing a liquid mixture comprising (i) starting materials for matrixparticles which are present in one or more forms selected from the groupconsisting of sols containing particles constituting matrix particlesand powders of the matrix particles, the matrix particles having aprimary particle with an average particle diameter of from 0.001 to 0.3μm; and (ii) starting materials for daughter particles which are presentin one or more forms selected from the group consisting of solscontaining daughter particles and powders of the daughter particles, thedaughter particles having a primary particle with an average particlediameter of from 0.001 to 0.1 μm, and treating the liquid mixture in amill and/or an apparatus for high-pressure dispersion, to therebyproduce composite fine particles wherein the daughter particles and thematrix particles are aggregated; (b) coating the composite fineparticles obtained in step (a) with an inorganic material; (c)subjecting the composite fine particles coated with the inorganicmaterial obtained in step (b) to a water-repellent treatment; and (d')dispersing in an oil agent the composite fine particles subjected to thewater-repellent treatment obtained in step (c).
 20. Cosmetics comprisingultraviolet shielding composite fine particles as defined in claim 1.21. Cosmetics comprising the dispersion oil agent of the ultravioletshielding composite fine particles as defined in claim
 15. 22. Thecosmetics according to claim 20, wherein an amount of said ultravioletshielding composite fine particles is from 0.01 to 50% by weight. 23.The cosmetics according to claim 20, further containing an ultravioletprotecting agent.
 24. The cosmetics according to claim 20, wherein SPFmeasured by using an analyser "SPF-290," manufactured by The OptometricsGroup is not less than 8, and wherein ΔE*ab before and after skinapplication is not more than 3 as defined according to JIS Z8729-1980.25. A method of shielding skin from ultraviolet light which comprisesapplying to said skin, a cosmetic composition comprising ultravioletshielding composite particles according to claim 1.